Implement basic rendering

Woo actioncontroller

lib/active_model/serializer/adapter/null_adapter.rb

@@ -6,10 +6,10 @@ module ActiveModel
           @serializer = serializer
         end
 
-        def to_json
+        def to_json(options={})
           @serializer.attributes.each_with_object({}) do |(attr, value), h|
             h[attr] = value
-          end.to_json
+          end.to_json # FIXME: why does passing options here cause {}?
         end
       end
     end