active_loaders is a gem that takes care of automatically doing “includes” for you when you’re using ActiveModel Serializers, and then also allows you to write queries for more complex preloading logic in a reusable way. It uses your serializer as a manifest to preload the data you need from the DB. It supports ActiveRecord and Sequel.

I had a talk about it at RUG::Berlin: http://www.ustream.tv/recorded/63090203 - the talk starts around 36 min

The gem lives here: https://github.com/kundi/active_loaders