private function forceSlash()
    {
        // add a trailing slash to the current URL
        $url = $this->getCurrentFull() . '/';
        // if there is a query string in the current request
        $queryString = $this->getServer('QUERY_STRING');
        if (!empty($queryString)) {
            // add the query string to the redirect URL
            $url .= '?' . $queryString;
        }
        $this->redirect($url);
    }