packaging a controller as a gem for re-use?

Hey all... Rails-Super-Newbie question:

I'm trying to package a controller as a gem for rails 3. How do I
make that happen? Should it be an Engine? Is it possible to put my
specs in it as well? Can someone give me some gentle beginner
pointers? I'm having a pretty tough time with the docs and my lack of
google-fu.

Thanks!