Hack to allow for dependency on modules hosted in github private repositories, accessed by SSH

I thought I'd share the edits I made in order to support pulling module dependencies from private github repositories.  In general, it would be nice if there was an official way to register SSH keys that are used by npm when setting up and launching a dyno for a nodeJS app.  Please consider my pull request as a feature request together with a less than ideal sample implementation

Best regards,
Mike Lang
Third Iron, LLC