composite-primary-keys/composite_primary_keys — pull request #239 by nhocki (2014-09-30 20:26:20+00:00)
Title: Remove singleton classes on CPK relations

Extract CPK methods to its own module and extending instead of opening the singleton class. This fixes `Marshal.dump` so caching relations works again.

I also removed some deprecation warnings on the AR::Base classes (on scopes) and fixed the broken test on MySQL.

This is similar to #169 but works with Rails 4.