public function add($domain_key, $owner_uid, $target_uid)
 {
     // error_log('in the add method of better friends **********');
     // error_log("domain=".$domain_key." owner=".$owner_uid." target=".$target_uid);
     if (!$domain_key || !$owner_uid || !$target_uid) {
         return false;
     } elseif (is_array($this->get($domain_key, $owner_uid)) && array_search($target_uid, $this->get($domain_key, $owner_uid)) !== false) {
         return false;
     }
     // if the owner_uid and target_uid are already friends
     $friend = new RingsideFriend();
     $friend->domain_key = $domain_key;
     $friend->from_id = $owner_uid;
     $friend->to_id = $target_uid;
     $friend->access = 1;
     $friend->status = 2;
     if ($friend->trySave()) {
         return true;
     } else {
         throw new Exception("[BetterFriendsImpl] could not create friend with domain={$domain_key}, owner_uid={$owner_uid}, target_uid={$target_uid}");
     }
 }