Adding documentation to the README file as per issue #7
Adding documentation to the README file as per issue #7

Taken augmented functions documentations from the [authentication middleware](https://github.com/jaredhanson/passport/blob/5334ee0fa52ab5f5225ddee695697432e0565679/lib/middleware/authenticate.js#L178) to describe the augmented methods as per issue #7
jaredhanson/passport-strategy