Spree, Rails 3, and theming

Question

Well, I've been trying to change the default theme of spree by following this tutorial

http://blog.endpoint.com/2010/01/rails-ecommerce-spree-hooks-tutorial.html

But the homepage doesn't change at all, well since the tutorial is meant for rails 2, I'm just wondering what do I need to change from the tutorial to make it work with rails 3?

Simpler solution than using hooks is welcomed. Also while I'm at it, is there a way to undo the command you run in rails like maybe uninstalling an extension.