Support for Rails 2.3.x

Hi @nashby this is the pull request in order to add the rails 2.3.x support.

I clean up the code in order to be more tidy, becuase last night in order to do it fast it was horrible :), I think that right now is a little bit better.

Also add the part for the setup for Rails 2.3.x in the README file.

Please let me know if you need or want something else for this pull request.

Thanks a lot!
Agustin