public function updateJoinGroup(Request $request)
{
$this->validate($request, ['join_group' => 'required']);
$groupId = $request->get('join_group');
$joinConfig = \app('xe.config')->get('user.join');
$joinConfig->set('joinGroup', $groupId);
\app('xe.config')->modify($joinConfig);
return XePresenter::makeApi(['type' => 'success', 'message' => '기본 가입 그룹이 변경되었습니다.', 'groupId' => $groupId]);
}