Initial code, json is generated using as_json() methods overrides in image.rb and user.rb models.
Converted as_json() calls to serializers in the app/serializers/ directory.
Added initializer as config/initializers/serializer.rb to remove root node in the json generated by serializer.
Merge branch 'master' of github.com:xunker/active_model_serializer_presentation_urug_july_23_2013