Add documentation on code review guidelines

docs/contributing/code-review.rst

@@ -0,0 +1,44 @@
+.. _contributing/code-review:
+
+======================
+Code Review guidelines
+======================
+
+This document outlines general guidelines to follow when you are making
+or reviewing a Pull Request.
+
+Have empathy
+============
+
+We recommend reading `On Empathy & Pull Requests <https://slack.engineering/on-empathy-pull-requests-979e4257d158>`_
+and `How about code reviews <https://slack.engineering/how-about-code-reviews-2695fb10d034>`_
+to learn more about being empathetic in code reviews.
+
+Write documentation
+===================
+
+If your pull request touches any code, you must write or update documentation
+for it. For this project, documentation is a lot more important than the code.
+If a feature is not documented, it does not exist. If a behavior is not documented, 
+it is a bug. 
+
+Do not worry about having perfect documentation! Documentation improves over
+time. The requirement is to have documentation before merging a pull request,
+not to have *perfect* documentation before merging a pull request.
+
+See :ref:`contributing/docs` for guidelines on writing documentation.
+
+Write tests
+===========
+
+If your pull request touches any code, you must write unit or integration tests
+to exercise it. This helps validate & communicate that your pull request works
+the way you think it does. It also makes sure you do not accidentally break
+other code, and makes it harder for future pull requests to break the code
+added in your pull request.
+
+Since TLJH is a distribution that integrates many JupyterHub components,
+integration tests provide more value for effort than unit tests do. Unit
+tests are easier to write & faster to run, so if the code being changed
+feels exhaustively unit-testable, write unit tests too. When in doubt,
+add more tests.

docs/contributing/docs.rst

@@ -1,3 +1,5 @@
+.. _contributing/docs:
+
 =====================
 Writing documentation
 =====================

docs/index.rst

@@ -116,4 +116,5 @@ to people contributing in various ways.
    :titlesonly:
 
    contributing/docs
+   contributing/code-review
    contributing/dev-setup