Add CONTRIBUTING.md (#66)

* Add CONTRIBUTING.md

* Update CONRIBUTING.md

* Rename to CONTRIBUTING.md

CONTRIBUTING.md

@@ -0,0 +1,14 @@
+# CONTRIBUTING
+
+When contributing to this repository, please first discuss the change you wish to
+make via [issue](https://github.com/jwplayer/buildpipe-buildkite-plugin/issues).
+
+Please note we have a [code of conduct](https://github.com/jwplayer/buildpipe-buildkite-plugin/blob/master/CODE_OF_CONDUCT.md),
+please follow it in all your interactions with the project.
+
+## Releasing
+
+1. Update documentation and `hook/command` to new version number.
+1. Run `make build` to generate `buildpipe-linux` binary.
+1. Add notes to `CHANGELOG.md`.
+1. Create a new release in GitHub. Attach `buildpipe-linux` binary.