Add link to Code of Conduct

CONTRIBUTING.md

@@ -0,0 +1,30 @@
+We love pull requests from everyone. By participating in this project, you
+agree to abide by the thoughtbot [code of conduct]. Here’s a quick guide:
+
+[code of conduct]: https://thoughtbot.com/open-source-code-of-conduct
+
+1. Fork the repository.
+2. Make your changes in a topic branch.
+3. Squash your commits into a single one (more on that
+   [here](http://gitready.com/advanced/2009/02/10/squashing-commits-with-rebase.html)).
+4. Rebase against `origin/master`, push to your fork and submit a pull request.
+
+At this point you’re waiting on us. We like to at least comment on, if not
+accept, pull requests within three business days (and, typically, one business
+day). We may suggest some changes or improvements or alternatives.
+
+Some things that will increase the chance that your pull request is accepted:
+
+* Write your code according to the [thoughtbot Style Guide][guide]
+* Fix a bug, refactor code or expand an existing feature.
+* Use the right syntax and naming conventions.
+* Update parts of the documentation that are affected by your contribution.
+
+[guide]: https://github.com/thoughtbot/guides/tree/master/style
+
+**Git Commit Messages**
+
+* Capitalize your commit messages.
+* Start your message with a verb.
+* Use present tense.
+* Refer to the issue/PR number in your squashed commit message.

README.md

@@ -46,6 +46,21 @@ We’ve also included some handy shortcuts with Proteus:
   proteus deploy
   ```
 
+## Contributing
+
+If you'd like to contribute a feature or bugfix: Thanks! To make sure your
+fix/feature has a high chance of being included, please read the following
+guidelines:
+
+1. Fork the repository
+2. Make your changes
+3. Push your branch to your fork
+4. Post a [pull request](https://github.com/thoughtbot/proteus/compare).
+
+Please see [CONTRIBUTING.md](CONTRIBUTING.md) for more details on contributing and running test.
+
+Thank you to all [the contributors](https://github.com/thoughtbot/proteus-middleman/contributors)!
+
 ## Credits
 
 [![thoughtbot](http://images.thoughtbot.com/bourbon/thoughtbot-logo.svg)](http://thoughtbot.com)