Created a patch for rails so that generators can be loaded from gems managed by bunlder

Hi,

I am working on creating datamapper generators for rails3 and ran into
a problem of loading the generators from a gem. The problem was that
the generators would not be loaded when it was in gem. I think this
was a bug in rails so a created a patch for it and submitted it on the
lighthouse rails bug tracker (https://rails.lighthouseapp.com/projects/
8994-ruby-on-rails/tickets/3603). This is my first patch I have
submitted to rails so I would really appreciate any comments and
feedback.

Thanks,

Josh