* Add `CONTRIBUTING.md` file to GitHub, to help new contributors. PR [#255](https://github.com/tiangolo/fastapi/pull/255) by [@wshayes](https://github.com/wshayes).
* Add support for Pydantic's `skip_defaults`:
* There's a new *path operation decorator* parameter `response_model_skip_defaults`.
* The name of the parameter will most probably change in a future version to `response_skip_defaults`, `model_skip_defaults` or something similar.