/**
  * @return string
  */
 protected function getAppID()
 {
     if (class_exists('OpenGraph')) {
         return OpenGraph::get_config('application_id');
     } else {
         return Config::inst()->get('FBLikeButtonExtension', 'application_id');
     }
 }
 protected function getConfigurableField($dbField, $configField)
 {
     $value = OpenGraph::get_config($configField);
     if ($value == 'SiteConfig') {
         return $this->owner->getField($dbField);
     }
     return $value;
 }