Diffrent is a very simple way to do ActiveRecord version diffing. It provides a convenient interface to two other libraries (Diffy and Vestal Versions), combining their functionality. It makes no assumption about what web framework you're using - it can be used in Sinatra, Padrino, Rails, or with no framework at all.

Publishus allows active record models and associations to be published and exist both in a 'current' and 'live' state