In the course of creating a basic RoR CMS, we've decided to
authenticate admin users via LDAP authentication. We already have
OpenLDAP up and running and a full directory set-up.

What is needed is some RoR code that can be plugged into the admin
login area of our application (give clear instructions on that) and
will verify not only if the user in question is an LDAP user, but also
grant/deny access based on their GID. The URL's included below made
attempts at this but are either insecure, poorly documented, or just
plain broken. The webserver (which is seperate from the LDAP server)
has all the LDAP-related plugins, etc installed.

http://wiki.rubyonrails.com/rails/pages/LDAPFunctions
http://www.pearware.org/articles/2005/05/23/ldap-authentication-in-rails
http://wiki.rubyonrails.org/rails/pages/HowtoAuthenticateViaLdap