Add release documentation

MANIFEST.in

@@ -6,3 +6,4 @@ include requirements.txt
 include .coveragerc
 include .codecov.yml
 recursive-include tests *.py
+recursive-include docs *.md

docs/how-to-release.md

@@ -0,0 +1,31 @@
+# How to release `matrix-synapse-ldap3`
+
+Releasing `matrix-synapse-ldap3` involves bumping the version number, creating
+a new tag on Github, then uploading release packages to
+[PyPi](https://pypi.org).
+
+You will need push access to this repo as well as an account on PyPi with push
+access to the
+[matrix-synapse-ldap3](https://pypi.org/project/matrix-synapse-ldap3/) package.
+
+## Git repository
+
+1. Edit the `__version__` variable of `ldap_auth_provider.py` to the new release
+version. This repository uses [Semantic Versioning](https://semver.org/).
+
+1. Commit and push with the commit message `X.Y.Z`.
+
+1. Create a git tag with `git tag -s vX.Y.Z`. Set the first line of the message
+   to `vX.Y.Z`, and the rest to the changes since the last release (looking at
+   the commit history can help).
+
+1. Push the tag with `git push origin tag vX.Y.Z`
+
+## Uploading to PyPi
+
+Ensure you have access to the `twine` command.
+
+1. Run `python setup.py sdist` to build the package
+
+1. `twine upload dist/matrix-synapse-ldap3-X.Y.Z.tar.gz` to upload the package
+   to PyPi.