Store password reset requests in database (#610)

* Store password reset requests in database

Signed-off-by: Rob Watson <rfwatson@users.noreply.github.com>

* Refactor password reset request expiry handling

* Integrate sqlite

* Fix formatting

migrations/postgres/2019-05-30-173029_create_password_reset_requests_table/down.sql

@@ -0,0 +1 @@
+DROP TABLE password_reset_requests;

migrations/postgres/2019-05-30-173029_create_password_reset_requests_table/up.sql

@@ -0,0 +1,9 @@
+CREATE TABLE password_reset_requests (
+  id SERIAL PRIMARY KEY,
+  email VARCHAR NOT NULL,
+  token VARCHAR NOT NULL,
+  expiration_date TIMESTAMP NOT NULL
+);
+
+CREATE INDEX password_reset_requests_token ON password_reset_requests (token);
+CREATE UNIQUE INDEX password_reset_requests_email ON password_reset_requests (email);