serializer_detail_class is required on DetailSerializerMixin

[mirskiy]

Per the docs, "If you use DetailSerializerMixin and don't specify serializer_detail_class attribute, then serializer_class will be used."

However, it serializer_detail_class is not included, I get an error: AssertionError: 'StaffViewSet' should include a 'serializer_detail_class' attribute

Not a big deal, but figured docs or code should be updated to match.

Assert is https://github.com/chibisov/drf-extensions/blob/master/rest_framework_extensions/mixins.py#L24

[auvipy]

PR welcome :)

[mirskiy]

Sure, which do you want changed - code or docs?

[auvipy]

the docs should be the first if the code changes are not that vital :)