Split part and reaction_part

Now, reactions should always end up on the bottom of a message group,
instead of sometimes being in the middle.

db/migrations/0007-split-part-and-reaction-part.sql

@@ -0,0 +1,24 @@
+BEGIN TRANSACTION;
+
+-- Add column reaction_part to event_message, copying the existing value from part
+
+CREATE TABLE "new_event_message" (
+	"event_id"	TEXT NOT NULL,
+	"event_type"	TEXT,
+	"event_subtype"	TEXT,
+	"message_id"	TEXT NOT NULL,
+	"part"	INTEGER NOT NULL,
+	"reaction_part" INTEGER NOT NULL,
+	"source"	INTEGER NOT NULL,
+	PRIMARY KEY("message_id","event_id")
+) WITHOUT ROWID;
+
+INSERT INTO new_event_message SELECT event_id, event_type, event_subtype, message_id, part, part, source FROM event_message;
+
+DROP TABLE event_message;
+
+ALTER TABLE new_event_message RENAME TO event_message;
+
+COMMIT;
+
+VACUUM;