Store edit timestamp in database to deduplicate edits. Fixes #86

database/upgrades/19-message-edit-ts.postgres.sql

@@ -0,0 +1,15 @@
+-- v19: Replace dc_edit_index with dc_edit_timestamp
+-- transaction: off
+BEGIN;
+
+ALTER TABLE reaction DROP CONSTRAINT reaction_message_fkey;
+ALTER TABLE message DROP CONSTRAINT message_pkey;
+ALTER TABLE message DROP COLUMN dc_edit_index;
+ALTER TABLE reaction DROP COLUMN _dc_first_edit_index;
+ALTER TABLE message ADD PRIMARY KEY (dcid, dc_attachment_id, dc_chan_id, dc_chan_receiver);
+ALTER TABLE reaction ADD CONSTRAINT reaction_message_fkey FOREIGN KEY (dc_msg_id, dc_first_attachment_id, dc_chan_id, dc_chan_receiver) REFERENCES message (dcid, dc_attachment_id, dc_chan_id, dc_chan_receiver) ON DELETE CASCADE;
+
+ALTER TABLE message ADD COLUMN dc_edit_timestamp BIGINT NOT NULL DEFAULT 0;
+ALTER TABLE message ALTER COLUMN dc_edit_timestamp DROP DEFAULT;
+
+COMMIT;