Inherit from CustomBackboneAPIView and define a serialize_item method.
Return a dict with modified data

Example:

class MyModelApi(CustomBackboneAPIView):
    base_queryset = ...
    serialize_fields = ...

    def serialize_item(self, item):
        d = super(MyModelApi, self).serialize_item(item)
        d['tags'] = ...
        return dict

- have generic create, read, update, delete functions (so data that does
  not directly map to a model can be modified through an API). Use
  specific model class for models.

The latest version of backbone requires a valid json response in order to trigger success/error callbacks so this patch just returns an empty json object instead of an empty string.

Never return empty response