Create a separate CONTRIBUTING.md file.

CONTRIBUTING.md

@@ -0,0 +1,8 @@
+## Contributing
+
+Contributions are welcome, but please follow these contributor guidelines:
+
+- Create an issue on [the issue tracker](https://github.com/intoli/exodus/issues/new) to discuss potential changes before submitting a pull request.
+- Include at least one test to cover any new functionality or bug fixes.
+- Make sure that all of your tests are passing and that there are no merge conflicts.
+- You agree to sign the project's [Contributor License Agreement](https://www.clahub.com/agreements/intoli/exodus).

README.md

@@ -519,8 +519,7 @@ tox
 
 ## Contributing
 
-Contributions are welcome, but please create an issue on [the issue tracker](https://github.com/intoli/exodus/issues/new) first to discuss the contribution first.
-New feature additions should include tests and it's a requirement that all tests must pass before pull requests are merged.
+Contributions are welcome, but please follow these contributor guideline that are outlined in [CONTRIBUTING.md](CONTRIBUTING.md).
 
 
 ## License