Add a contributing file

.github/CONTRIBUTING.md

@@ -0,0 +1,40 @@
+Guidelines
+==========
+
+When contributing to Omnivore, please follow the style of the file you
+are editing. For most code running `yarn lint` should tell you if
+your code meets are style.
+
+
+License
+=======
+
+Omnivore is licensed under the AGPL license.
+
+CLA
+=======
+
+Contributions are taken under [Omnivore's CLA](https://cla-assistant.io/omnivore-app/omnivore).
+
+Code Review
+=======
+We require code review from a [CODEOWNER](https://github.com/omnivore-app/omnivore/blob/main/.github/CODEOWNERS) before merging a pull request.
+
+Testing
+=======
+
+Pull requests are automatically tested using GitHub Actions. Wed
+usually only merge a pull request if it causes no regressions in a
+test run.
+
+When you submit a pull request, one of two things happens:
+
+* If you are a new contributor, GitHub will ask for permissions (on
+  the pull request) to test it. A maintainer will reply to approve
+  the test run if they find the patch appropriate.
+* If you have previously contributed, GitHub will test your pull 
+  request as soon as a test machine is available.
+
+Once tests are passing on your pull request it will be reviewed, 
+merged, and deployed by a maintiner. We deploy around ten times
+a day, so your changes should hit production quickly.