add class

src/server/views/widget/alert_siteurl_undefined.html

@@ -1,5 +1,5 @@
 {% if !getConfig('crowi', 'app:siteUrl') %}
-<div class="alert alert-danger mb-0 px-4 py-2">
+<div class="alert-url-not-set alert alert-danger mb-0 px-4 py-2">
   <i class="icon-exclamation"></i>
   {{ t("security_setting.alert_siteUrl_is_not_set", { link:t('App Settings')}) }}
 </div>