public function getMigrations(Updater $updater)
    {
        // many different migrations are available to be used via $this->migration factory
        $migration1 = $this->migration->db->changeColumnType('log_visit', 'example', 'BOOLEAN NOT NULL');
        // you can also define custom SQL migrations. If you need to bind parameters, use `->boundSql()`
        $migration2 = $this->migration->db->sql($sqlQuery = 'SELECT 1');

        return array(
            // $migration1,
            // $migration2
        );
    }