Is your Rails app secure? Really? Maybe you need to perform a major check-up of your Rails application to make sure.
Here's a <ahref="http://rubythis.blogspot.com/2006/11/rails-security-checklist.html">comprehensive list</a> that will take you through the most common mistakes and forgotten security risks in your Rails application.
It's a great post. Print it, hang it on your wall and create secure Rails apps from now on.