Updates url to fix issue #2

CONTRIBUTING.md

@@ -26,7 +26,8 @@ Once you've identified one of the issues above that you feel you can contribute
    several people starting working on the same thing.
 2. **[Fork](https://help.github.com/articles/fork-a-repo/) this repository**. This makes your own version of this project you can edit and use.
 3. **[Make your changes](https://guides.github.com/activities/forking/#making-changes)**! You can do this in the GitHub interface on your own local machine (we *strongly recommend that you create a new branch* to make your changes). Once you're happy with your changes...
-4. **Submit a [pull request](https://help.github.com/articles/proposing-changes-to-a-project-with-pull-requests/)**. This opens a discussion around your project and lets the project lead know you are proposing changes.
+4. **Submit a [pull request](https://help.github.com/enterprise/2.7/user/articles/proposing-changes-to-a-project-with-pull-requests/)**. This opens a discussion around your project and lets the project lead know you are proposing changes.
+
 
 First time contributing to open source? Check out this *free* series, [How to Contribute to an Open Source Project on GitHub](https://egghead.io/series/how-to-contribute-to-an-open-source-project-on-github).