static public function connect(Application $app,
                                   $dsn,
                                  $username,
                                  $password,
                                  $options = [])
    {
        $options += [
            \PDO::ATTR_ERRMODE =>\PDO::ERRMODE_EXCEPTION,
            \PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES'utf8';",
            \PDO::MYSQL_ATTR_FOUND_ROWS => true
        ];

        $connection = new \PDO($dsn, $username, $password, $options);
        return new DB($app, $connection);
    }