Add CONTRIBUTING.md

Also add a "Contributing" section to the README.

Author: mhagger

CONTRIBUTING.md

@@ -0,0 +1,32 @@
+## Contributing
+
+[fork]: https://github.com/github/git-sizer/fork
+[pr]: https://github.com/github/git-sizer/compare
+[code-of-conduct]: CODE_OF_CONDUCT.md
+
+Hi there! We're thrilled that you'd like to contribute to this project. Your help is essential for keeping it great.
+
+Please note that this project is released with a [Contributor Code of Conduct][code-of-conduct]. By participating in this project you agree to abide by its terms.
+
+## Submitting a pull request
+
+1. [Fork][fork] and clone the repository
+2. Configure and install the dependencies: `script/bootstrap`
+3. Make sure the tests pass on your machine: `make test`
+4. Create a new branch: `git checkout -b my-branch-name`
+5. Make your change, add tests, and make sure the tests still pass
+6. Push to your fork and [submit a pull request][pr]
+7. Pat your self on the back and wait for your pull request to be reviewed and merged.
+
+Here are a few things you can do that will increase the likelihood of your pull request being accepted:
+
+- Make sure that your code is formatted correctly: `make gofmt`.
+- Write tests.
+- 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).
+
+## Resources
+
+- [How to Contribute to Open Source](https://opensource.guide/how-to-contribute/)
+- [Using Pull Requests](https://help.github.com/articles/about-pull-requests/)
+- [GitHub Help](https://help.github.com)

README.md

@@ -196,3 +196,8 @@ $ git-sizer
 ```
 
 This repository is mischievously constructed to have a pathological tree structure, with the same directories repeated over and over again. As a result, even though the entire repository is less than 20 kb in size, when checked out it would explode into over a billion directories containing over ten billion files. (`git-sizer` prints `∞` for the blob count because the true number has overflowed the 32-bit counter used for that field.)
+
+
+## Contributing
+
+`git-sizer` is in regular use and is still under active development. If you would like to help out, please see [`CONTRIBUTING.md`](CONTRIBUTING.md).