• Rails Security Checklist by Eliot Sykes
• Ruby’s class system
• Ruby blocks and closures
• Ruby method arguments
• Rails Composer – Starter applications for Rails developers, generated by Rails Composer. It’s like ‘rails new’ on steroids. Open source; free to use.
• Zen Rails Base App – Base or “skeleton” application for Ruby on Rails projects. Built to minimize the time spent writing boilerplate code and performing repetitive setup tasks.

Ruby related blog posts and Ruby on Rails posts.