Merge pull request #669 from vector-im/bwindels/contrib

Add guide for new contributers

CONTRIBUTING.md

@@ -0,0 +1,150 @@
+Contributing code to hydrogen-web
+==================================
+
+Everyone is welcome to contribute code to hydrogen-web, provided that they are
+willing to license their contributions under the same license as the project
+itself. We follow a simple 'inbound=outbound' model for contributions: the act
+of submitting an 'inbound' contribution means that the contributor agrees to
+license the code under the same terms as the project's overall 'outbound'
+license - in this case, Apache Software License v2 (see
+[LICENSE](LICENSE)).
+
+How to contribute
+-----------------
+
+The preferred and easiest way to contribute changes to the project is to fork
+it on github, and then create a pull request to ask us to pull your changes
+into our repo (https://help.github.com/articles/using-pull-requests/)
+
+We use GitHub's pull request workflow to review the contribution, and either
+ask you to make any refinements needed or merge it and make them ourselves.
+
+Things that should go into your PR description:
+ * References to any bugs fixed by the change (in GitHub's `Fixes` notation)
+ * Describe the why and what is changing in the PR description so it's easy for
+   onlookers and reviewers to onboard and context switch.
+ * If your PR makes visual changes, include both **before** and **after** screenshots
+   to easily compare and discuss what's changing.
+ * Include a step-by-step testing strategy so that a reviewer can check out the
+   code locally and easily get to the point of testing your change.
+ * Add comments to the diff for the reviewer that might help them to understand
+   why the change is necessary or how they might better understand and review it.
+
+We use continuous integration, and all pull requests get automatically tested:
+if your change breaks the build, then the PR will show that there are failed
+checks, so please check back after a few minutes.
+
+Tests
+-----
+If your PR is a feature then we require that the PR also includes tests.
+These need to test that your feature works as expected and ideally test edge cases too.
+
+Tests are written as unit tests by exporting a `tests` function from the file to be tested.
+The function returns an object where the key is the test label, and the value is a 
+function that accepts an [assert](https://nodejs.org/api/assert.html) object, and return a Promise or nothing.
+
+Note that there is currently a limitation that files that are not indirectly included from `src/platform/web/main.js` won't be found by the runner.
+
+You can run the tests by running `yarn test`.
+This uses the [impunity](https://github.com/bwindels/impunity) runner.
+
+We don't require tests for bug fixes.
+
+In the future we may formalise this more.
+
+Code style
+----------
+The js-sdk aims to target TypeScript/ES6. All new files should be written in
+TypeScript and existing files should use ES6 principles where possible.
+
+Please disable any automatic formatting tools you may have active.
+If present, you'll be asked to undo any unrelated whitespace changes during code review.
+
+Members should not be exported as a default export in general.
+In general, avoid using `export default`.
+
+The remaining code-style for hydrogen is [in the process of being documented](codestyle.md), but
+contributors are encouraged to read the
+[code style document for matrix-react-sdk](https://github.com/matrix-org/matrix-react-sdk/blob/master/code_style.md)
+and follow the principles set out there.
+
+Please ensure your changes match the cosmetic style of the existing project,
+and ***never*** mix cosmetic and functional changes in the same commit, as it
+makes it horribly hard to review otherwise.
+
+Attribution
+-----------
+If you change or create a file, feel free to add yourself to the copyright holders
+in the license header of that file.
+
+Sign off
+--------
+In order to have a concrete record that your contribution is intentional
+and you agree to license it under the same terms as the project's license, we've
+adopted the same lightweight approach that the Linux Kernel
+(https://www.kernel.org/doc/Documentation/SubmittingPatches), Docker
+(https://github.com/docker/docker/blob/master/CONTRIBUTING.md), and many other
+projects use: the DCO (Developer Certificate of Origin:
+http://developercertificate.org/). This is a simple declaration that you wrote
+the contribution or otherwise have the right to contribute it to Matrix:
+
+```
+Developer Certificate of Origin
+Version 1.1
+
+Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
+660 York Street, Suite 102,
+San Francisco, CA 94110 USA
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+(a) The contribution was created in whole or in part by me and I
+    have the right to submit it under the open source license
+    indicated in the file; or
+
+(b) The contribution is based upon previous work that, to the best
+    of my knowledge, is covered under an appropriate open source
+    license and I have the right under that license to submit that
+    work with modifications, whether created in whole or in part
+    by me, under the same open source license (unless I am
+    permitted to submit under a different license), as indicated
+    in the file; or
+
+(c) The contribution was provided directly to me by some other
+    person who certified (a), (b) or (c) and I have not modified
+    it.
+
+(d) I understand and agree that this project and the contribution
+    are public and that a record of the contribution (including all
+    personal information I submit with it, including my sign-off) is
+    maintained indefinitely and may be redistributed consistent with
+    this project or the open source license(s) involved.
+```
+
+If you agree to this for your contribution, then all that's needed is to
+include the line in your commit or pull request comment:
+
+```
+Signed-off-by: Your Name <your@email.example.org>
+```
+
+We accept contributions under a legally identifiable name, such as your name on
+government documentation or common-law names (names claimed by legitimate usage
+or repute). Unfortunately, we cannot accept anonymous contributions at this
+time.
+
+Git allows you to add this signoff automatically when using the `-s` flag to
+`git commit`, which uses the name and email set in your `user.name` and
+`user.email` git configs.
+
+If you forgot to sign off your commits before making your pull request and are
+on Git 2.17+ you can mass signoff using rebase:
+
+```
+git rebase --signoff origin/develop
+```