Adds a CONTRIBUTING.md (issue #392)

CONTRIBUTING.md

@@ -0,0 +1,51 @@
+# How to contribute
+
+## Setup
+
+```sh
+git clone https://github.com/danger/danger-js.git
+cd danger-js
+
+# if you don't have yarn installed
+npm install -g yarn
+
+yarn install
+```
+
+You can then verify your install by running the tests, and the linters:
+
+```sh
+yarn test
+yarn lint
+```
+
+The fixers for both tslint and prettier will be applied when you commit, and on a push your code will be verified
+that it compiles.
+
+### What is the TODO?
+
+Check the issues, I try and keep my short term perspective there. Long term is in the [VISION.md](VISION.md).
+
+### Releasing a new version of Danger
+
+Following [this commit](https://github.com/danger/danger-js/commit/a26ac3b3bd4f002acd37f6a363c8e74c9d5039ab) as a model:
+
+-   Checkout the `master` branch. Ensure your working tree is clean, and make sure you have the latest changes by running `git pull`.
+-   Update `package.json` with the new version - for the sake of this example, the new version is **0.21.0**.
+-   Modify `changelog.md`, adding a new `### 0.21.0` heading under the `### Master` heading at the top of the file.
+-   Commit both changes with the commit message **Version bump**.
+-   Tag this commit - `git tag 0.21.0`.
+-   Push the commit and tag to master - `git push origin master --follow-tags`. Travis CI will build the tagged commit and publish that tagged version to NPM.
+
+:ship:
+
+## License, Contributor's Guidelines and Code of Conduct
+
+We try to keep as much discussion as possible in GitHub issues, but also have a pretty inactive Slack --- if you'd like an invite, ping [@Orta](https://twitter.com/orta/) a DM on Twitter with your email. It's mostly interesting if you want to stay on top of Danger without all the emails from GitHub.
+
+> This project is open source under the MIT license, which means you have full access to the source code and can modify it to fit your own needs.
+>
+> This project subscribes to the [Moya Contributors Guidelines](https://github.com/Moya/contributors) which TLDR: means we give out push access easily and often.
+>
+> Contributors subscribe to the [Contributor Code of Conduct](http://contributor-covenant.org/version/1/3/0/) based on the [Contributor Covenant](http://contributor-covenant.org) version 1.3.0.
+

README.md

@@ -46,7 +46,7 @@ Some quick links to get you started:
 
 ## This thing is broken, I should help improve it!
 
-Awesommmmee.
+Awesommmmee. Everything you need is down below. You can also refer to [CONTRIBUTING](CONTRIBUTING.md) file where you'll find the same information listed below.
 
 ```sh
 git clone https://github.com/danger/danger-js.git