How to package model classes for use in Rails and elsewhere

I have what is probably a relatively simple question.

I have a collection of model classes that subclass ActiveRecord in

I would also like to use these classes in: a) other Rails apps and b)
other non-rails apps that use ruby.

Is there a "best practice" for bundling/requiring this collection of
classes so that I don't have to "hand-copy" them into different

Should I make a gem (the classes wouldn't be relevant to anyone else)
or is there some other DRY approach?