function check_login($username, $password) {

    $db = Database::getInstance();

    $query = new Query(
        sprintf("
            SELECT password
            FROM users
            WHERE username=%s
            ",
            $db->quote($this->username)
        )
    );

    if ($query->getNumberOfRows() == 1) {
        $result = $query->getResult();

        $hash = $result['password'];
        $salt = substr( $hash, 0, 8 );

        $password = $salt . sha1($salt . $password);

        if ($password == $salt) {
            return true;
        } else {
            return false;
        }
    } else {
        return false;
    }
}