public function login(Request $request)
 {
     $email = $request->input('email');
     $password = $request->input('password');
     if (!$email || !$password) {
         return response()->json(array('error' => 'You must provide an email address and password.'), 400);
     }
     $hashedPassword = User::hashedPassword($password);
     $user = User::where(['password' => $hashedPassword, 'email' => $email])->first();
     if (!$user) {
         return response()->json(array('error' => 'Unable to find a user matching that email address and password.'), 401);
     }
     $token = Token::generateForUser($user->id);
     return response()->json(['user' => $user, 'token' => $token->token], 200, []);
 }