public static function create($user, $siteMember = null, $roleSlug = null)
 {
     // Find Current Site
     $site = Site::findByName(Yii::$app->cmgCore->getSiteName());
     if (!isset($siteMember)) {
         $siteMember = new SiteMember();
         if (isset($roleSlug)) {
             $role = RoleService::findBySlug($roleSlug);
             $siteMember->roleId = $role->id;
         } else {
             $role = RoleService::findBySlug(CoreGlobal::ROLE_USER);
             $siteMember->roleId = $role->id;
         }
     }
     $siteMember->siteId = $site->id;
     $siteMember->userId = $user->id;
     $siteMember->save();
     return $siteMember;
 }