Adopt the PyPA Code of Conduct

Author: d0ugal

README.md

@@ -18,6 +18,11 @@ Project documentation with Markdown.
 - IRC channel: `#mkdocs` on freenode.
 - Discussions and support: <https://groups.google.com/forum/#!forum/mkdocs>
 
+## Code of Conduct
+
+Everyone interacting in the MkDocs project's codebases, issue trackers, chat
+rooms, and mailing lists is expected to follow the [PyPA Code of Conduct].
+
 [appveyor-image]: https://img.shields.io/appveyor/ci/d0ugal/mkdocs/master.png
 [appveyor-link]: https://ci.appveyor.com/project/d0ugal/mkdocs
 [codecov-image]: http://codecov.io/github/mkdocs/mkdocs/coverage.svg?branch=master
@@ -33,3 +38,5 @@ Project documentation with Markdown.
 
 [mkdocs]: http://www.mkdocs.org
 [release-notes]: http://www.mkdocs.org/about/release-notes/
+
+[PyPA Code of Conduct]: https://www.pypa.io/en/latest/code-of-conduct/

docs/about/contributing.md

@@ -10,6 +10,11 @@ ways, a few examples are:
 - Documentation improvements
 - Bug reports and patch reviews
 
+## Code of Conduct
+
+Everyone interacting in the MkDocs project's codebases, issue trackers, chat
+rooms, and mailing lists is expected to follow the [PyPA Code of Conduct].
+
 ## Reporting an Issue
 
 Please include as much detail as you can. Let us know your platform and MkDocs
@@ -61,3 +66,4 @@ most likely need to have tests and documentation if it is a new feature.
 [virtualenv]: https://virtualenv.pypa.io/en/latest/userguide.html
 [tox]: https://tox.readthedocs.io/en/latest/
 [travis]: https://travis-ci.org/repositories
+[PyPA Code of Conduct]: https://www.pypa.io/en/latest/code-of-conduct/