public function execute()
 {
     $code = waRequest::post('code', '', waRequest::TYPE_STRING_TRIM);
     if (!$code) {
         $this->errors[] = _w("Unknown code");
         return;
     }
     $currency_model = new shopCurrencyModel();
     if (!$currency_model->add($code)) {
         $this->errors[] = _w("Unknown code");
         return;
     }
 }