Remove old db migration that was merged into initial schema

database/upgrades/2019-05-16-message-delete-cascade.go

@@ -1,31 +0,0 @@
-package upgrades
-
-import (
-	"database/sql"
-)
-
-func init() {
-	upgrades[1] = upgrade{"Add ON DELETE CASCADE to message table", func(tx *sql.Tx, ctx context) error {
-		if ctx.dialect == SQLite {
-			// SQLite doesn't support constraint updates, but it isn't that careful with constraints anyway.
-			return nil
-		}
-		res, _ := ctx.db.Query(`SELECT EXISTS(SELECT constraint_name FROM information_schema.table_constraints
-			WHERE table_name='message' AND constraint_name='message_chat_jid_fkey')`)
-		var exists bool
-		_ = res.Scan(&exists)
-		if exists {
-			_, err := tx.Exec("ALTER TABLE message DROP CONSTRAINT IF EXISTS message_chat_jid_fkey")
-			if err != nil {
-				return err
-			}
-			_, err = tx.Exec(`ALTER TABLE message ADD CONSTRAINT message_chat_jid_fkey
-				FOREIGN KEY (chat_jid, chat_receiver) REFERENCES portal(jid, receiver)
-				ON DELETE CASCADE`)
-			if err != nil {
-				return err
-			}
-		}
-		return nil
-	}}
-}