Authentication in Ruby On Rails

Basic User Authentication In Rails – This article is great.  It covers everything you need to fully implement authentication in your Ruby On Rails sites.  What I like most about it is that it is a full step-by-step how to roll your own.  There are several other authentication engines out there, but this allows you to customize and tweak it to meet your needs, plus you know all the details of how it works.  Another bonus…unit tests are included in the article.