This project is from an OAuth2.0 tutorial I followed from the YouTube channel "The Net Ninja" listed below. The tutorial uses Passport.js and Google Strategy to implement an authentication protocol utilizing Google+ API.
https://www.youtube.com/watch?v=sakQbeRjgwg&list=PL4cUxeGkcC9jdm7QX143aMLAqyM-jTZ2x