* Refactor documentation to make a simpler and shorter [Tutorial - User Guide](https://fastapi.tiangolo.com/tutorial/) and an additional [Advanced User Guide](https://fastapi.tiangolo.com/advanced/) with all the additional docs. PR [#887](https://github.com/tiangolo/fastapi/pull/887).
* Tweak external links, Markdown format, typos. PR [#881](https://github.com/tiangolo/fastapi/pull/881).
* Fix bug in tutorial handling HTTP Basic Auth `username` and `password`. PR [#865](https://github.com/tiangolo/fastapi/pull/865) by [@isaevpd](https://github.com/isaevpd).