function add_subscribers(ProjectDataObject $object)
 {
     if (logged_user()->isGuest()) {
         flash_error(lang('no access permissions'));
         ajx_current("empty");
         return;
     }
     $log_info = "";
     $subscribers = array_var($_POST, 'subscribers');
     $object->clearSubscriptions();
     if (is_array($subscribers)) {
         foreach ($subscribers as $key => $checked) {
             $user_id = substr($key, 5);
             if ($checked == "checked") {
                 $user = Users::findById($user_id);
                 if ($user instanceof User) {
                     $object->subscribeUser($user);
                     $phone_num = Users::getPhoneNumberCustomProperty($user_id);
                     $sms_obj = new SmsController();
                     $sms_obj->prepareSubscriberSms($user->getDisplayName(), $object->getTitle(), get_class($object));
                     $sms_obj->sendSms($phone_num);
                     $log_info .= ($log_info == "" ? "" : ",") . $user->getId();
                 }
             }
         }
         if ($log_info != "") {
             ApplicationLogs::createLog($object, $object->getWorkspaces(), ApplicationLogs::ACTION_SUBSCRIBE, false, true, true, $log_info);
         }
     }
 }