static $has_one = array(
                  'Advertiser' => 'Advertiser',
                  'AdvertImage' => 'FittedImage',
   );   
   
   static $searchable_fields = array(
                  'TargetURL' => 'ExactMatchFilter',
                  'Title' => 'ExactMatchFilter',
   );
   static $summary_fields = array(
                  'TargetURL',
                  'AdvertImageThumbnail',
                  'Title',
                  'ToolTipTitle',
   );
   
   public function AdvertImageThumbnail() {
    return $this->AdvertImage()->CMSThumbnail();
   }