public function profile()
    {
        $user = $this->auth->getUser();
        $username = $this->request->request('username');
        $nickname = $this->request->request('nickname');
        $bio = $this->request->request('bio');
        $avatar = $this->request->request('avatar');
        $exists = \app\common\model\User::where('username', $username)->where('id', '<>', $this->auth->id)->find();
        if ($exists)
        {
            $this->error(__('Username already exists'));
        }
        $user->username = $username;
        $user->nickname = $nickname;
        $user->bio = $bio;
        $user->avatar = $avatar;
        $user->save();
        $this->success();
    }