Implement attachments for Discord -> Matrix

database/migrations/02-attachments.sql

@@ -0,0 +1,12 @@
+CREATE TABLE attachment (
+	channel_id TEXT NOT NULL,
+	receiver TEXT NOT NULL,
+
+	discord_message_id TEXT NOT NULL,
+	discord_attachment_id TEXT NOT NULL,
+
+	matrix_event_id TEXT NOT NULL UNIQUE,
+
+	PRIMARY KEY(discord_attachment_id, matrix_event_id),
+	FOREIGN KEY(channel_id, receiver) REFERENCES portal(channel_id, receiver) ON DELETE CASCADE
+);

database/migrations/migrations.go

@@ -40,6 +40,7 @@ func Run(db *sql.DB, baseLog log.Logger) error {
 		migrator.WithLogger(logger),
 		migrator.Migrations(
 			migrationFromFile("01-initial.sql"),
+			migrationFromFile("02-attachments.sql"),
 		),
 	)
 	if err != nil {