update the contributing doc based on the template

CONTRIBUTING.md

@@ -1,3 +1,41 @@
-# Contributing to Git Hawser
+## Contributing to Git Hawser
 
-TBD
+Hi there! We're thrilled that you'd like to contribute to this project. Your
+help is essential for keeping it great.
+
+## Submitting a pull request
+
+0. [Fork][] and clone the repository
+0. Configure and install the dependencies: `script/bootstrap`
+0. Make sure the tests pass on your machine: `script/test`
+0. Create a new branch: `git checkout -b my-branch-name`
+0. Make your change, add tests, and make sure the tests still pass
+0. Push to your fork and [submit a pull request][pr]
+0. Pat your self on the back and wait for your pull request to be reviewed.
+
+Here are a few things you can do that will increase the likelihood of your pull request being accepted:
+
+- Follow the [style guide][style] where possible.
+- Write tests.
+- Update documentation as necessary.  Commands have [man pages][./docs/man].
+- Keep your change as focused as possible. If there are multiple changes you
+would like to make that are not dependent upon each other, consider submitting
+them as separate pull requests.
+- Write a [good commit message](http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html).
+
+## Updating 3rd party packages
+
+0. Update `Godeps`.
+0. Run `script/vendor` to update the code in the `.vendor/src` directory.
+0. Commit the change.  Hawser vendors the full source code in the repository.
+0. Submit a pull request.
+
+## Resources
+
+- [Contributing to Open Source on GitHub](https://guides.github.com/activities/contributing-to-open-source/)
+- [Using Pull Requests](https://help.github.com/articles/using-pull-requests/)
+- [GitHub Help](https://help.github.com)
+
+[fork]: https://github.com/hawser/git-hawser/fork
+[pr]: https://github.com/hawser/git-hawser/compare
+[style]: https://github.com/golang/go/wiki/CodeReviewComments