Returns the names of all related fields for model class.

def _get_related_fields(self, model):
        "Returns the names of all related fields for model class."
        reverse_fk = self._get_all_related_objects(model)
        reverse_m2m = self._get_all_related_many_to_many_objects(model)

        fields = tuple(reverse_fk + reverse_m2m)
        names = tuple([x.get_accessor_name() for x in fields])

        return {
            ':related': dict(list(zip(names, fields))),
        }