message: Add installation instructions.
diff: `feathers-authentication` adds shared [PassportJS](http://passportjs.org/) authentication for Feathers HTTP REST and WebSockets services using [JSON Web Tokens](http://jwt.io/).
  +## Installation
  +
  +```
  +npm install feathers-authentication --save
  +```
  +
  ## Documentation
  Please refer to the [Authentication documentation](http://docs.feathersjs.com/authentication/readme.html) for more details:
  