link to admin page in about

server/templates/about.html.j2

@@ -26,6 +26,8 @@
       {%- endfor %}
     </ul>
 
+    <p>Instance owners can login at <a href="/admin">/admin</a> for settings and more information.</p>
+
     <h4>Table Explanations</h4>
     <ul>
       <li><code>Country</code> for the host country reported in the instance wiki.</li>