Inclusion of add user instructions for overlay

docbook/auth-server-docs/reference/en/en-US/modules/server-installation.xml

@@ -128,6 +128,12 @@ bin/add-user.[sh|bat] -r master -u <username> -p <password>
 ]]></programlisting>
                 Then restart the server.
             </para>
+            <para>
+                For <literal>keycloak-overlay</literal>, please make sure to use:
+<programlisting><![CDATA[
+bin/add-user-keycloak.[sh|bat] -r master -u <username> -p <password>
+]]></programlisting>
+            </para>
             </section>
 
         <section>