protected function appendUrlOptions($url, $options)
    {
        $options = array_only($options, [
            'welcome_msg',
            'timezone',
            'anonymous',
            'minimal'
        ]);

        $boolean_keys = ['minimal', 'anonymous'];
        foreach ($boolean_keys as $key) {
            if (isset($options[$key])) {
                $options[$key] = $this->booleanToString($options[$key]);
            } else {
                $options[$key] = 'true';
            }
        }

        return $url . '?' . http_build_query($options);
    }