Sort follow requests, followers, and following by updated_at

[blackle]

so it is consistent with mastodon and other AP implementations, where the most recent followers are shown first.

[tsmethurst]

To make sure database queries don't get slow, we need to update some indexes to make this work properly, otherwise the new indexes create temp b-trees.

Now:

If we change the query without updating indexes:

This is the index suggested by sqlite3:

So in a migration, these four indexes:

follow_requests_account_id_idx
follow_requests_target_account_id_idx
follows_account_id_idx
follows_target_account_id_idx

need to be dropped and recreated, by adding updated_at desc at the end. For example:

CREATE INDEX "follow_requests_account_id_idx" ON "follow_requests" (
	"account_id",
	"updated_at"	DESC
)

Once that's done, this should be good to go :) But I think I'd rather get 0.4.0 out before adding another migration, so take your time.

[blackle]

added the migration. explain query plan seems not to use a temporary b-tree anymore!