public function login()
 {
     //        dump(session('admin'));
     if (session('admin.id') > 0) {
         $this->redirect('Admin/Index/all');
         exit;
     }
     if (IS_POST) {
         $admin = $this->Admin->getByPhone(I('post.phone'));
         if ($admin && md5(I('post.password')) == $admin['password']) {
             session('admin', $admin);
             $this->redirect('Admin/Index/all');
             exit;
         }
     }
     $this->display();
 }