remove use of rust in migration (#704)

* remove use of rust in migration

rewrite use_timelines_for_feed in pure sql
delete tantivy related migration. It will require reintroducing tantivy
initialisation in docs

fix #702

* Fill timeline from migrations

should fix #692 , but probably require some testing

migrations/sqlite/2019-12-10-104935_fill_timelines/down.sql

@@ -0,0 +1,8 @@
+DELETE FROM timeline WHERE id IN
+	(
+		SELECT timeline.id FROM timeline
+		INNER JOIN timeline_definition ON timeline.timeline_id = timeline_definition.id
+		WHERE timeline_definition.query LIKE 'followed or [%]' OR
+			timeline_definition.query = 'local' OR
+			timeline_definition.query = 'all'
+	);

migrations/sqlite/2019-12-10-104935_fill_timelines/up.sql

@@ -0,0 +1,17 @@
+INSERT INTO timeline (post_id, timeline_id)
+	SELECT posts.id,timeline_definition.id FROM posts,timeline_definition
+	WHERE timeline_definition.query = 'all';
+
+INSERT INTO timeline (post_id, timeline_id)
+	SELECT posts.id,timeline_definition.id FROM posts,timeline_definition
+	INNER JOIN blogs ON posts.blog_id = blogs.id
+	INNER JOIN instances ON blogs.instance_id = instances.id
+	WHERE timeline_definition.query = 'local' and instances.local = true;
+
+INSERT INTO timeline (post_id, timeline_id)
+	SELECT posts.id,timeline_definition.id FROM posts
+	INNER JOIN blog_authors ON posts.blog_id = blog_authors.blog_id
+	LEFT JOIN follows ON blog_authors.author_id = follows.following_id
+	INNER JOIN timeline_definition ON follows.follower_id = timeline_definition.user_id
+		or blog_authors.author_id = timeline_definition.user_id
+	WHERE timeline_definition.query LIKE 'followed or [%]';