private function fillGroupWithMembers(ProjectUGroup $ugroup)
 {
     $source_ugroup = $ugroup->getSourceGroup();
     if ($source_ugroup) {
         $this->addUGroupBinding($ugroup, $source_ugroup);
     } else {
         foreach ($ugroup->getMembers() as $user) {
             $this->addUserToGroupWithoutFlush($user, $ugroup);
         }
     }
 }