Added example image to the auditor documentation

doc/administration/auditor_users.md

@@ -17,4 +17,8 @@ on the GitLab instance.
 The `auditor` role is _not_ a read-only version of the `admin` role. The auditor will not be
 able to access the project settings pages, or the Admin Area.
 
+A user access level can be set to ‘Auditor’ in the Admin Area
+
+![Admin Area Form](auditor_access_form.png)
+
 [998]: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/998