improve: run data migrations in a transaction

So that any failures are rolled back. We use a single transaction for
all migrations because on-prem deploys will likely want to keep the
old schema if any of the migrations in a new version fail.

internal/server/data/data.go

@@ -32,22 +32,33 @@ func NewDB(connection gorm.Dialector, loadDBKey func(db GormTxn) error) (*DB, er
 		return nil, fmt.Errorf("db conn: %w", err)
 	}
 	dataDB := &DB{DB: db}
+	tx, err := dataDB.Begin(context.TODO())
+	if err != nil {
+		return nil, err
+	}
 
 	opts := migrator.Options{
 		InitSchema: initializeSchema,
-		LoadKey: func(tx migrator.DB) error {
+		LoadKey: func(_ migrator.DB) error {
 			if loadDBKey == nil {
 				return nil
 			}
 			// TODO: use the passed in tx instead of dataDB once the queries
 			// used by loadDBKey are ported to sql
-			return loadDBKey(dataDB)
+			return loadDBKey(tx)
 		},
 	}
-	m := migrator.New(dataDB, opts, migrations())
+	m := migrator.New(tx, opts, migrations())
 	if err := m.Migrate(); err != nil {
+		if err := tx.Rollback(); err != nil {
+			logging.L.Warn().Err(err).Msg("failed to rollback")
+		}
 		return nil, fmt.Errorf("migration failed: %w", err)
 	}
+	if err := tx.Commit(); err != nil {
+		return nil, fmt.Errorf("commit migrations: %w", err)
+	}
+
 	if err := initialize(dataDB); err != nil {
 		return nil, fmt.Errorf("initialize database: %w", err)
 	}