Add CONTRIBUTING link to readme

README.md

@@ -51,7 +51,7 @@ You'll want to fork this repository and deploy your own image generator.
 
 1. Click the fork button at the top right of GitHub
 2. Clone the repo to your local machine with `git clone URL_OF_FORKED_REPO_HERE`
-3. Make changes by swapping out images, changing colors, etc
+3. Make changes by swapping out images, changing colors, etc (see [contributing](https://github.com/styfle/og-image/blob/master/CONTRIBUTING.md) for more)
 4. Deploy by running `now` from the CLI (if you don't already have it, run `npm install -g now`)
 
 Alternatively, you can do a one-click to deploy with the button below.