Add a contribution guide

CONTRIBUTING.md

@@ -0,0 +1,135 @@
+Toot contribution guide
+=======================
+
+Firstly, thank you for contributing to toot!
+
+Relevant links which will be referenced below:
+
+* [toot documentation](https://toot.readthedocs.io/)
+* [toot-discuss mailing list](https://lists.sr.ht/~ihabunek/toot-discuss)
+  used for discussion as well as accepting patches
+* [toot project on github](https://github.com/ihabunek/toot)
+  here you can report issues and submit pull requests
+* #toot IRC channel on [libera.chat](https://libera.chat)
+
+## Code of conduct
+
+Please be kind and patient. Toot is governed by one human with a full time job.
+
+## I have a question
+
+First, check if your question is addressed in the documentation or the mailing
+list. If not, feel free to send an email to the mailing list. You may want to
+subscribe to the mailing list to receive replies.
+
+Alternatively, you can ask your question on the IRC channel and ping me
+(ihabunek). You may have to wait for a response, please be patient.
+
+Please don't open Github issues for questions.
+
+## I want to contribute
+
+### Reporting a bug
+
+First check you're using the
+[latest version](https://github.com/ihabunek/toot/releases/) of toot and verify
+the bug is present in this version.
+
+Search Github issues to check the bug hasn't already been reported.
+
+To report a bug open an
+[issue on Github](https://github.com/ihabunek/toot/issues) or send an
+email to the [mailing list](https://lists.sr.ht/~ihabunek/toot-discuss).
+
+* Run `toot env` and include its contents in the bug report.
+* Explain the behavior you would expect and the actual behavior.
+* Please provide as much context as possible and describe the reproduction steps
+  that someone else can follow to recreate the issue on their own.
+
+### Suggesting enhancements
+
+This includes suggesting new features or changes to existing ones.
+
+Search Github issues to check the enhancement has not already been requested. If
+it hasn't, [open a new issue](https://github.com/ihabunek/toot/issues).
+
+Your request will be reviewed to see if it's a good fit for toot. Implementing
+requested features depends on the available time and energy of the maintainer
+and other contributors. Be patient.
+
+### Contributing code
+
+When contributing to toot, please only submit code that you have authored or
+code whose license allows it to be included in toot. You agree that the code
+you submit will be published under the [toot license](LICENSE).
+
+#### Setting up a dev environment
+
+Check out toot (or a fork) and install it into a virtual environment.
+
+```
+git clone git@github.com:ihabunek/toot.git
+cd toot
+python3 -m venv _env
+source _env/bin/activate
+pip install --editable .
+pip install -r requirements-dev.txt
+pip install -r requirements-test.txt
+```
+
+While the virtual env is active, running `toot` will execute the one you checked
+out. This allows you to make changes and test them.
+
+Run tests:
+
+```
+pytest
+```
+
+Check code style:
+
+```
+flake8
+```
+
+#### Crafting good commits
+
+Please put some effort into breaking your contribution up into a series of well
+formed commits. If you're unsure what this means, there is a good guide
+available at https://cbea.ms/git-commit/.
+
+Rules for commits:
+
+* each commit should ideally contain only one change
+* don't bundle multiple unrelated changes into a single commit
+* write descriptive and well formatted commit messages
+
+Rules for commit messages:
+
+* separate subject from body with a blank line
+* limit the subject line to 50 characters
+* capitalize the subject line
+* do not end the subject line with a period
+* use the imperative mood in the subject line
+* wrap the body at 72 characters
+* use the body to explain what and why vs. how
+
+If you use vim to write your commit messages, it will already enforce these
+rules for you.
+
+#### Submitting patches
+
+To submit your code either open
+[a pull request](https://github.com/ihabunek/toot/pulls) on Github, or send
+patch(es) to [the mailing list](https://lists.sr.ht/~ihabunek/toot-discuss).
+
+If sending to the mailing list, patches should be sent using `git send-email`.
+If you're unsure how to do this, there is a good guide at
+https://git-send-email.io/.
+
+---
+
+Parts of this guide were taken from the following sources:
+
+* https://contributing.md/
+* https://cbea.ms/git-commit/