Note: DO NOT USE
This will probably take some time before it will be better than other available tools for working with Rails on Emacs.
At first my focus is on making navigation of Rails projects fast. I'm a massive fan of Rails.vim. I'm very efficient with it and continue to use it daily because it's simply the best environment for hacking Rails applications, but I'm currently into Emacs and would like something as nice.
So hold onto your butts...