Add contributing docs adapted from Girder

CONTRIBUTING.md

@@ -0,0 +1,69 @@
+Contributing to Girder Worker
+=============================
+
+There are many ways to contribute to Girder Worker, with varying levels of effort.  Do try to
+look through the documentation first if something is unclear, and let us know how we can
+do better.
+
+  * Ask a question in the [Gitter Forum](https://gitter.im/girder/girder_worker)
+  * Submit a feature request or bug, or add to the discussion on the [Girder Worker issue tracker](https://github.com/girder/girder_worker/issues)
+  * Submit a [Pull Request](https://github.com/girder/girder_worker/pulls) to improve Girder Worker or its documentation
+
+We encourage a range of Pull Requests, from patches that include passing tests and
+documentation, all the way down to half-baked ideas that launch discussions.
+
+The PR Process, Travis CI, and Related Gotchas
+----------------------------------------------
+
+#### How to submit a PR ?
+
+If you are new to Girder Worker development and you don't have push access to the Girder Worker
+repository, here are the steps:
+
+1. [Fork and clone](https://help.github.com/articles/fork-a-repo/) the repository.
+3. Create a branch.
+4. [Push](https://help.github.com/articles/pushing-to-a-remote/) the branch to your GitHub fork.
+5. Create a [Pull Request](https://github.com/girder/girder_worker/pulls).
+
+This corresponds to the `Fork & Pull Model` mentioned in the [GitHub flow](https://guides.github.com/introduction/flow/index.html)
+guides.
+
+If you have push access to Girder Worker repository, you could simply push your branch
+into the main repository and create a [Pull Request](https://github.com/girder/girder_worker/pulls). This corresponds to the
+`Shared Repository Model` and will facilitate other developers to checkout your
+topic without having to [configure a remote](https://help.github.com/articles/configuring-a-remote-for-a-fork/).
+It will also simplify the workflow when you are _co-developing_ a branch.
+
+When submitting a PR, make sure to add a `Cc: @girder_worker/developers` comment to notify Girder Worker
+developers of your awesome contributions. Based on the
+comments posted by the reviewers, you may have to revisit your patches.
+
+### How to integrate a PR ?
+
+Getting your contributions integrated is relatively straightforward, here
+is the checklist:
+
+* All tests pass
+* Consensus is reached. This usually means that at least one reviewer added a `LGTM` comment
+and a reasonable amount of time passed without anyone objecting. `LGTM` is an
+acronym for _Looks Good to Me_.
+
+Next, there are two scenarios:
+* You do NOT have push access: A Girder Worker core developer will integrate your PR.
+* You have push access: Simply click on the "Merge pull request" button.
+
+Then, click on the "Delete branch" button that appears afterward.
+
+#### Automatic testing of pull requests
+
+When you submit a PR to the Girder Worker repo, Travis CI will run the full build on two different branches
+
+  * The commit at the head of the PR branch, the `push` build
+  * The head of the PR branch that is then merged into `master`, the `pr` branch
+
+The Travis build will run according to the [.travis.yml file](/.travis.yml), which is
+useful as an example for how to set up your own environment for testing.
+
+The tests that run in Travis are harnessed with CTest, which submits the results of its
+automated testing to [Girder Worker's CDash dashboard](http://my.cdash.org/index.php?project=girder_worker)
+where the test and coverage results can be easily visualized and explored.

README.rst

@@ -11,6 +11,12 @@ and from various data sources, including Girder.
 
 Visit the `documentation <http://girder-worker.readthedocs.org>`_ for more details and API documentation.
 
+For questions, comments, or to get in touch with the maintainers, head to our `Gitter Forum
+<https://gitter.im/girder/girder_worker>`_.
+
+We'd love for you to `contribute to Girder Worker <CONTRIBUTING.md>`_.
+
+
 .. |build-status| image:: https://travis-ci.org/girder/girder_worker.png?branch=master
     :target: https://travis-ci.org/girder/girder_worker
     :alt: Build Status