Merge pull request #664 from kentcdodds/pr/update-contributing

add note about AVA mantra in contributing guidelines

Author: jamestalmage

contributing.md

@@ -45,3 +45,5 @@ We have a [chat](https://gitter.im/sindresorhus/ava). Jump in there and lurk, ta
 - Use a clear and descriptive title for the pull request and commits.
 - Write a convincing description of why we should land your pull request. It's your job to convince us. Answer "why" it's needed and provide use-cases.
 - You might be asked to do changes to your pull request. There's never a need to open another pull request. [Just update the existing one.](https://github.com/RichardLitt/docs/blob/master/amending-a-commit-guide.md)
+
+Note: when making code changes, try to remember AVA's mantra (stolen from Python) of having preferably one way to do something. For example, a request to add an alias to part of the API ([like this](https://github.com/sindresorhus/ava/pull/663)) will likely be rejected without some other substantial benefit.