add sqlite migrations

we move our PostgreSQL specific migrations to a subdirectory.
The SQLite migrations have been created by running `diesel` against a
copy, and then fixing what's broken.
In the end i reduced all modifications to a single create, since we
*are* starting out fresh with SQLite.

n.b.: i'm not entirely happy with the results yet, because diesel
heavily modifies our `plume-models/src/schema.rs`.
I'll keep fiddling until we have the same types between the two
databases.

migrations/postgres/00000000000000_diesel_initial_setup/down.sql

@@ -0,0 +1,6 @@
+-- This file was automatically created by Diesel to setup helper functions
+-- and other internal bookkeeping. This file is safe to edit, any future
+-- changes will be added to existing projects as new migrations.
+
+DROP FUNCTION IF EXISTS diesel_manage_updated_at(_tbl regclass);
+DROP FUNCTION IF EXISTS diesel_set_updated_at();

migrations/postgres/00000000000000_diesel_initial_setup/up.sql

@@ -0,0 +1,36 @@
+-- This file was automatically created by Diesel to setup helper functions
+-- and other internal bookkeeping. This file is safe to edit, any future
+-- changes will be added to existing projects as new migrations.
+
+
+
+
+-- Sets up a trigger for the given table to automatically set a column called
+-- `updated_at` whenever the row is modified (unless `updated_at` was included
+-- in the modified columns)
+--
+-- # Example
+--
+-- ```sql
+-- CREATE TABLE users (id SERIAL PRIMARY KEY, updated_at TIMESTAMP NOT NULL DEFAULT NOW());
+--
+-- SELECT diesel_manage_updated_at('users');
+-- ```
+CREATE OR REPLACE FUNCTION diesel_manage_updated_at(_tbl regclass) RETURNS VOID AS $$
+BEGIN
+    EXECUTE format('CREATE TRIGGER set_updated_at BEFORE UPDATE ON %s
+                    FOR EACH ROW EXECUTE PROCEDURE diesel_set_updated_at()', _tbl);
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE OR REPLACE FUNCTION diesel_set_updated_at() RETURNS trigger AS $$
+BEGIN
+    IF (
+        NEW IS DISTINCT FROM OLD AND
+        NEW.updated_at IS NOT DISTINCT FROM OLD.updated_at
+    ) THEN
+        NEW.updated_at := current_timestamp;
+    END IF;
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;

migrations/postgres/2018-04-22-093322_create_instances/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE instances;

migrations/postgres/2018-04-22-093322_create_instances/up.sql

@@ -0,0 +1,9 @@
+-- Your SQL goes here
+CREATE TABLE instances (
+    id SERIAL PRIMARY KEY,
+    local_domain VARCHAR NOT NULL,
+    public_domain VARCHAR NOT NULL,
+    name VARCHAR NOT NULL,
+    local BOOLEAN NOT NULL DEFAULT 'f',
+    blocked BOOLEAN NOT NULL DEFAULT 'f'
+)

migrations/postgres/2018-04-22-151330_create_user/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE users;

migrations/postgres/2018-04-22-151330_create_user/up.sql

@@ -0,0 +1,13 @@
+-- Your SQL goes here
+CREATE TABLE users (
+    id SERIAL PRIMARY KEY,
+    username VARCHAR NOT NULL,
+    display_name VARCHAR NOT NULL DEFAULT '',
+    outbox_url VARCHAR NOT NULL,
+    inbox_url VARCHAR NOT NULL,
+    is_admin BOOLEAN NOT NULL DEFAULT 'f',
+    summary TEXT NOT NULL DEFAULT '',
+    email TEXT,
+    hashed_password TEXT,
+    instance_id INTEGER REFERENCES instances(id) ON DELETE CASCADE NOT NULL
+);

migrations/postgres/2018-04-23-101717_create_blogs/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE blogs;

migrations/postgres/2018-04-23-101717_create_blogs/up.sql

@@ -0,0 +1,10 @@
+-- Your SQL goes here
+CREATE TABLE blogs (
+    id SERIAL PRIMARY KEY,
+    actor_id VARCHAR NOT NULL,
+    title VARCHAR NOT NULL,
+    summary TEXT NOT NULL DEFAULT '',
+    outbox_url VARCHAR NOT NULL,
+    inbox_url VARCHAR NOT NULL,
+    instance_id INTEGER REFERENCES instances(id) ON DELETE CASCADE NOT NULL
+)

migrations/postgres/2018-04-23-111655_create_blog_authors/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE blog_authors;

migrations/postgres/2018-04-23-111655_create_blog_authors/up.sql

@@ -0,0 +1,7 @@
+-- Your SQL goes here
+CREATE TABLE blog_authors (
+    id SERIAL PRIMARY KEY,
+    blog_id INTEGER REFERENCES blogs(id) ON DELETE CASCADE NOT NULL,
+    author_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL,
+    is_owner BOOLEAN NOT NULL DEFAULT 'f'
+)

migrations/postgres/2018-04-23-132822_create_posts/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE posts;

migrations/postgres/2018-04-23-132822_create_posts/up.sql

@@ -0,0 +1,10 @@
+-- Your SQL goes here
+CREATE TABLE posts (
+    id SERIAL PRIMARY KEY,
+    blog_id INTEGER REFERENCES blogs(id) ON DELETE CASCADE NOT NULL,
+    slug VARCHAR NOT NULL,
+    title VARCHAR NOT NULL,
+    content TEXT NOT NULL DEFAULT '',
+    published BOOLEAN NOT NULL DEFAULT 'f',
+    license VARCHAR NOT NULL DEFAULT 'CC-0'
+)

migrations/postgres/2018-04-23-142746_create_post_authors/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE post_authors;

migrations/postgres/2018-04-23-142746_create_post_authors/up.sql

@@ -0,0 +1,6 @@
+-- Your SQL goes here
+CREATE TABLE post_authors (
+    id SERIAL PRIMARY KEY,
+    post_id INTEGER REFERENCES posts(id) ON DELETE CASCADE NOT NULL,
+    author_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL
+)

migrations/postgres/2018-04-30-170445_timestamps/down.sql

@@ -0,0 +1,5 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE posts DROP COLUMN creation_date;
+ALTER TABLE blogs DROP COLUMN creation_date;
+ALTER TABLE users DROP COLUMN creation_date;
+ALTER TABLE instances DROP COLUMN creation_date;

migrations/postgres/2018-04-30-170445_timestamps/up.sql

@@ -0,0 +1,5 @@
+-- Your SQL goes here
+ALTER TABLE posts ADD COLUMN creation_date TIMESTAMP NOT NULL DEFAULT now();
+ALTER TABLE blogs ADD COLUMN creation_date TIMESTAMP NOT NULL DEFAULT now();
+ALTER TABLE users ADD COLUMN creation_date TIMESTAMP NOT NULL DEFAULT now();
+ALTER TABLE instances ADD COLUMN creation_date TIMESTAMP NOT NULL DEFAULT now();

migrations/postgres/2018-05-01-124607_create_follow/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE follows;

migrations/postgres/2018-05-01-124607_create_follow/up.sql

@@ -0,0 +1,6 @@
+-- Your SQL goes here
+CREATE TABLE follows (
+    id SERIAL PRIMARY KEY,
+    follower_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL,
+    following_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL
+)

migrations/postgres/2018-05-01-165325_add_ap_url/down.sql

@@ -0,0 +1,3 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE blogs DROP COLUMN ap_url;
+ALTER TABLE users DROP COLUMN ap_url;

migrations/postgres/2018-05-01-165325_add_ap_url/up.sql

@@ -0,0 +1,3 @@
+-- Your SQL goes here
+ALTER TABLE blogs ADD COLUMN ap_url TEXT NOT NULL default '';
+ALTER TABLE users ADD COLUMN ap_url TEXT NOT NULL default '';

migrations/postgres/2018-05-02-113930_drop_instance_local_domain/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE instances ADD COLUMN local_domain VARCHAR NOT NULL;

migrations/postgres/2018-05-02-113930_drop_instance_local_domain/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE instances DROP COLUMN local_domain;

migrations/postgres/2018-05-03-163427_user_add_keys/down.sql

@@ -0,0 +1,3 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE users DROP COLUMN private_key;
+ALTER TABLE users DROP COLUMN public_key;

migrations/postgres/2018-05-03-163427_user_add_keys/up.sql

@@ -0,0 +1,3 @@
+-- Your SQL goes here
+ALTER TABLE users ADD COLUMN private_key TEXT;
+ALTER TABLE users ADD COLUMN public_key TEXT NOT NULL DEFAULT '';

migrations/postgres/2018-05-03-182555_blogs_add_keys/down.sql

@@ -0,0 +1,3 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE blogs DROP COLUMN private_key;
+ALTER TABLE blogs DROP COLUMN public_key;

migrations/postgres/2018-05-03-182555_blogs_add_keys/up.sql

@@ -0,0 +1,3 @@
+-- Your SQL goes here
+ALTER TABLE blogs ADD COLUMN private_key TEXT;
+ALTER TABLE blogs ADD COLUMN public_key TEXT NOT NULL DEFAULT '';

migrations/postgres/2018-05-09-192013_create_comments/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE comments;

migrations/postgres/2018-05-09-192013_create_comments/up.sql

@@ -0,0 +1,12 @@
+-- Your SQL goes here
+CREATE TABLE comments (
+    id SERIAL PRIMARY KEY,
+    content TEXT NOT NULL DEFAULT '',
+    in_response_to_id INTEGER REFERENCES comments(id),    
+    post_id INTEGER REFERENCES posts(id) ON DELETE CASCADE NOT NULL,
+    author_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL,
+    creation_date TIMESTAMP NOT NULL DEFAULT now(),
+    ap_url VARCHAR,
+    sensitive BOOLEAN NOT NULL DEFAULT 'f',
+    spoiler_text TEXT NOT NULL DEFAULT ''
+)

migrations/postgres/2018-05-10-101553_posts_add_ap_url/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE posts DROP COLUMN ap_url;

migrations/postgres/2018-05-10-101553_posts_add_ap_url/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE posts ADD COLUMN ap_url VARCHAR NOT NULL DEFAULT '';

migrations/postgres/2018-05-10-154336_create_likes/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE likes;

migrations/postgres/2018-05-10-154336_create_likes/up.sql

@@ -0,0 +1,7 @@
+-- Your SQL goes here
+CREATE TABLE likes (
+    id SERIAL PRIMARY KEY,
+    user_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL,
+    post_id INTEGER REFERENCES posts(id) ON DELETE CASCADE NOT NULL,
+    creation_date TIMESTAMP NOT NULL DEFAULT now()
+)

migrations/postgres/2018-05-12-213456_likes_add_ap_url/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE likes DROP COLUMN ap_url;

migrations/postgres/2018-05-12-213456_likes_add_ap_url/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE likes ADD COLUMN ap_url VARCHAR NOT NULL default '';

migrations/postgres/2018-05-13-122311_create_notifications/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE notifications;

migrations/postgres/2018-05-13-122311_create_notifications/up.sql

@@ -0,0 +1,8 @@
+-- Your SQL goes here
+CREATE TABLE notifications (
+    id SERIAL PRIMARY KEY,
+    title VARCHAR NOT NULL DEFAULT '',
+    content TEXT,
+    link VARCHAR,
+    user_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL
+)

migrations/postgres/2018-05-13-175144_users_add_shared_inbox/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE users DROP COLUMN shared_inbox_url;

migrations/postgres/2018-05-13-175144_users_add_shared_inbox/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE users ADD COLUMN shared_inbox_url VARCHAR;

migrations/postgres/2018-05-19-091428_create_reshares/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE reshares;

migrations/postgres/2018-05-19-091428_create_reshares/up.sql

@@ -0,0 +1,8 @@
+-- Your SQL goes here
+CREATE TABLE reshares (
+    id SERIAL PRIMARY KEY,
+    user_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL,
+    post_id INTEGER REFERENCES posts(id) ON DELETE CASCADE NOT NULL,
+    ap_url VARCHAR NOT NULL DEFAULT '',
+    creation_date TIMESTAMP NOT NULL DEFAULT now()
+)

migrations/postgres/2018-05-24-100613_add_notifications_creation_date/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE notifications DROP COLUMN creation_date;

migrations/postgres/2018-05-24-100613_add_notifications_creation_date/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE notifications ADD COLUMN creation_date TIMESTAMP NOT NULL DEFAULT now();

migrations/postgres/2018-06-17-200302_notification_add_data/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE notifications DROP COLUMN data;

migrations/postgres/2018-06-17-200302_notification_add_data/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE notifications ADD COLUMN data VARCHAR;

migrations/postgres/2018-06-20-175532_create_mentions/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE mentions;

migrations/postgres/2018-06-20-175532_create_mentions/up.sql

@@ -0,0 +1,7 @@
+-- Your SQL goes here
+CREATE TABLE mentions (
+    id SERIAL PRIMARY KEY,
+    mentioned_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL,
+    post_id INTEGER REFERENCES posts(id) ON DELETE CASCADE,
+    comment_id INTEGER REFERENCES comments(id) ON DELETE CASCADE
+)

migrations/postgres/2018-06-20-194538_add_mentions_ap_url/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE mentions DROP COLUMN ap_url;

migrations/postgres/2018-06-20-194538_add_mentions_ap_url/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE mentions ADD COLUMN ap_url VARCHAR NOT NULL DEFAULT '';

migrations/postgres/2018-07-25-165754_refactor_notifications/down.sql

@@ -0,0 +1,8 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE notifications ADD COLUMN title VARCHAR NOT NULL;
+ALTER TABLE notifications ADD COLUMN content TEXT;
+ALTER TABLE notifications ADD COLUMN link VARCHAR;
+ALTER TABLE notifications ADD COLUMN data VARCHAR;
+
+ALTER TABLE notifications DROP COLUMN kind;
+ALTER TABLE notifications DROP COLUMN object_id;

migrations/postgres/2018-07-25-165754_refactor_notifications/up.sql

@@ -0,0 +1,8 @@
+-- Your SQL goes here
+ALTER TABLE notifications DROP COLUMN title;
+ALTER TABLE notifications DROP COLUMN content;
+ALTER TABLE notifications DROP COLUMN link;
+ALTER TABLE notifications DROP COLUMN data;
+
+ALTER TABLE notifications ADD COLUMN kind VARCHAR NOT NULL DEFAULT 'unknown';
+ALTER TABLE notifications ADD COLUMN object_id INTEGER NOT NULL DEFAULT 0;

migrations/postgres/2018-07-27-102221_user_add_followers_endpoint/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE users DROP COLUMN followers_endpoint;

migrations/postgres/2018-07-27-102221_user_add_followers_endpoint/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE users ADD COLUMN followers_endpoint VARCHAR NOT NULL DEFAULT '';

migrations/postgres/2018-07-27-125558_instance_customization/down.sql

@@ -0,0 +1,5 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE instances DROP COLUMN open_registrations;
+ALTER TABLE instances DROP COLUMN short_description;
+ALTER TABLE instances DROP COLUMN long_description;
+ALTER TABLE instances DROP COLUMN default_license;

migrations/postgres/2018-07-27-125558_instance_customization/up.sql

@@ -0,0 +1,5 @@
+-- Your SQL goes here
+ALTER TABLE instances ADD COLUMN open_registrations BOOLEAN NOT NULL DEFAULT 't';
+ALTER TABLE instances ADD COLUMN short_description TEXT NOT NULL DEFAULT '';
+ALTER TABLE instances ADD COLUMN long_description TEXT NOT NULL DEFAULT '';
+ALTER TABLE instances ADD COLUMN default_license TEXT NOT NULL DEFAULT 'CC-0';

migrations/postgres/2018-07-27-194816_instance_description_html/down.sql

@@ -0,0 +1,3 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE instances DROP COLUMN long_description_html;
+ALTER TABLE instances DROP COLUMN short_description_html;

migrations/postgres/2018-07-27-194816_instance_description_html/up.sql

@@ -0,0 +1,3 @@
+-- Your SQL goes here
+ALTER TABLE instances ADD COLUMN long_description_html VARCHAR NOT NULL DEFAULT '';
+ALTER TABLE instances ADD COLUMN short_description_html VARCHAR NOT NULL DEFAULT '';

migrations/postgres/2018-09-02-111458_create_medias/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE medias;

migrations/postgres/2018-09-02-111458_create_medias/up.sql

@@ -0,0 +1,10 @@
+-- Your SQL goes here
+CREATE TABLE medias (
+    id SERIAL PRIMARY KEY,
+    file_path TEXT NOT NULL DEFAULT '',
+    alt_text TEXT NOT NULL DEFAULT '',
+    is_remote BOOLEAN NOT NULL DEFAULT 'f',
+    remote_url TEXT,
+    sensitive BOOLEAN NOT NULL DEFAULT 'f',
+    content_warning TEXT
+)

migrations/postgres/2018-09-02-123623_medias_owner_id/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE medias DROP COLUMN owner_id;

migrations/postgres/2018-09-02-123623_medias_owner_id/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE medias ADD COLUMN owner_id INTEGER REFERENCES users(id) ON DELETE CASCADE NOT NULL;

migrations/postgres/2018-09-03-102510_users_add_avatar/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE users DROP COLUMN avatar_id;

migrations/postgres/2018-09-03-102510_users_add_avatar/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE users ADD COLUMN avatar_id INTEGER REFERENCES medias(id) ON DELETE CASCADE;

migrations/postgres/2018-09-03-170848_user_add_last_fetched_date/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE users DROP COLUMN last_fetched_date;

migrations/postgres/2018-09-03-170848_user_add_last_fetched_date/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE users ADD COLUMN last_fetched_date TIMESTAMP NOT NULL DEFAULT '2000-01-01 00:00:01';

migrations/postgres/2018-09-04-103017_follows_add_ap_url/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE follows DROP COLUMN ap_url;

migrations/postgres/2018-09-04-103017_follows_add_ap_url/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE follows ADD COLUMN ap_url TEXT NOT NULL DEFAULT '';

migrations/postgres/2018-09-04-104828_posts_add_subtitle/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE posts DROP COLUMN subtitle;

migrations/postgres/2018-09-04-104828_posts_add_subtitle/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE posts ADD COLUMN subtitle TEXT NOT NULL DEFAULT '';

migrations/postgres/2018-09-05-174106_create_tags/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+DROP TABLE tags;

migrations/postgres/2018-09-05-174106_create_tags/up.sql

@@ -0,0 +1,7 @@
+-- Your SQL goes here
+CREATE TABLE tags (
+    id SERIAL PRIMARY KEY,
+    tag TEXT NOT NULL DEFAULT '',
+    is_hastag BOOLEAN NOT NULL DEFAULT 'f',
+    post_id INTEGER REFERENCES posts(id) ON DELETE CASCADE NOT NULL
+)

migrations/postgres/2018-09-06-182637_posts_add_source/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE posts DROP COLUMN source;

migrations/postgres/2018-09-06-182637_posts_add_source/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE posts ADD COLUMN source TEXT NOT NULL DEFAULT '';

migrations/postgres/2018-09-07-212003_fix_avatar_deletion/down.sql

@@ -0,0 +1,7 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE users
+    DROP CONSTRAINT users_avatar_id_fkey,
+    ADD CONSTRAINT users_avatar_id_fkey
+    FOREIGN KEY (avatar_id)
+    REFERENCES medias(id)
+    ON DELETE CASCADE;

migrations/postgres/2018-09-07-212003_fix_avatar_deletion/up.sql

@@ -0,0 +1,7 @@
+-- Your SQL goes here
+ALTER TABLE users
+    DROP CONSTRAINT users_avatar_id_fkey,
+    ADD CONSTRAINT users_avatar_id_fkey
+    FOREIGN KEY (avatar_id)
+    REFERENCES medias(id)
+    ON DELETE SET NULL;