protected function registerUser($email, $facebookUserId)
    {
        $className = $this->userService->getUserClass();
        /** @var BaseUser $user */
        $user = (new  $className());
        $user->setEmail($email)
            ->setFacebookUserId($facebookUserId)
            ->setPlainPassword(base64_encode(random_bytes(20)));
        $this->userService->registerUser($user, UserService::SOURCE_TYPE_FACEBOOK);

        return $user;
    }