/**
  * @param array $payload
  * @param int $id
  * @return User|null
  */
 public function update(array $payload, $id)
 {
     $user = $this->user->find($id);
     if (!$user) {
         return null;
     }
     if (array_key_exists('member_id', $payload)) {
         return null;
     }
     $user->fill($payload)->save();
     return $user;
 }