I just released a new version of a gem called after_do, which you can use to easily add callbacks before/after a method is executed. I also wrote an introduction blog post about it - go ahead and check it out! :-)
I just created a Rails Beginner Cheat Sheet aimed at helping beginners remember all those basic concepts and commands, hopefully making their start into Ruby and Rails smoother. Feedback very welcome =)
Over time I've collected quite many resources ranging from beginner material about Ruby and Rails to more advanced resources. Most of the material is free. I hope that this collection of resources is beneficial to people, who are interested in Ruby/Rails regardless of their skill level.
You may have heard the news about github being hacked and the associated hype around the mass assignment vulnerability. In case you missed it: my new blog post Secure your Rails apps! tries to summarize what was going on, what this vulnerability is and how to protect against it.