rails-api/active_model_serializers — pull request #213 by michihuber (2013-02-26 10:25:59+00:00)
Title: Fix rendering nil with custom serializer

Fixes https://github.com/rails-api/active_model_serializers/issues/204

If the root object is nil, it doesn't try to convert it into a hash but renders it as is.
Custom roots are respected.