public function login($base)
 {
     $this->userOnly();
     $form = new LoginForm();
     if ($form->isSubmitted() && $form->validation->validate()) {
         if ($this->user->authenticate($form->get('username'), $form->get('password'))) {
             $this->flash('info', 'Welcome back ' . $form->get('username'));
             $this->refresh();
         }
         $base->set('error', 'Login gagal! Cek kembali username dan password Anda.');
     }
     $base->set('form', $form);
     $this->render('default/login.html');
 }