user display preferences options

What you're dealing with is the authenticate / authorize sequence.

Authenticate covers topics such as login / password / session access to the site. Authorize covers role (or other) based access within the site.

Google either for gems / plugins / discussions

restful_authentication plugin. also has roles for authorization. http://github.com/technoweenie/restful-authentication/tree/master http://railsforum.com/viewtopic.php?id=14216