public function login(LoginRequest $request)
 {
     $credentials = $request->only('password', 'email');
     if ($user = User::email($credentials['email'])->first()) {
         $password = $credentials['password'];
         if (Hash::check($password, $user->password)) {
             $access_token = AccessToken::userId($user->id)->first();
             if (!$access_token) {
                 $access_token = AccessToken::create(['user_id' => $user->id, 'token' => Hash::make($user->email . $user->name)]);
             }
             $data = ['email' => $user->email, 'name' => $user->name, 'token' => $access_token->token];
             return $this->respondSuccess('Successful Login', $data);
         } else {
             return $this->respondUnauthorized();
         }
     } else {
         return $this->respondUnauthorized();
     }
 }