public function addGroup(GroupModel $group)
 {
     if (!$group->getSlug()) {
         $this->warnings[] = new DataWarningGroupHasNoSlug();
         $group->createSlug();
     }
     if ($this->siteContainer['grouprepository']->loadBySlug($group->getSlug())) {
         $this->errors[] = new DataErrorTwoGroupsHaveSameSlugs();
     }
     $this->siteContainer['log']->info("Adding group", array('group' => $group->getDataForLoggerInfo()));
     $this->siteContainer['grouprepository']->create($group);
 }