public function perform()
    {
        $userField = $this->option('user-field', 'username');
        $passwordField = $this->option('password-field', 'password');

        $user = $this->getUser($this->form->data($userField));

        if (!$user || !$user->login($this->form->data($passwordField))) {
            $this->fail(I18n::translate('uniform-login-error'), $userField);
        }
    }