Many of Passport's strategies are based on HTTP sessions. At the moment, our application is just using simple cookies to store user IDs. To use Passport for third-party authentication, we'll need to add session support into our application. Express provides session support in the express-session module. First, we add this to our application:

> npm install express-session --save

We also need somewhere to store session data. Express supports a variety of session stores via additional modules. Redis is well suited to this task and we already have a Redis instance available. We can use the connect-redis module to store sessions in Redis:

> npm install connect-redis --save

We can now create a new configuration module to keep all our session logic in one place. Since this will return middleware, we'll put it in the middleware folder here src/middleware/sessions.js:

'use strict';

const session = require('express-session');

let config = {
    secret: process.env.SESSION_SECRET...