How to set Redis session store

I would like to set a sessionStore with Redis (to use with passport.socketio) anybody can point me in the right direction? I am using express@3.2.6 and connect-redis@1.4.7

I can set the sessionStore as a MemoryStore, and as a MongoStore, but cannot figure out how to do it with Redis

Using MemoryStore

 var express = require('express');
 var sessionStore = new express.session.MemoryStore(); 

Using MongoStore

var express = require('express');
var mongoose = require('mongoose');
var MongoStore = require('connect-mongo')(express);
mongoose.connect("mongodb://mydatabase_uri")
var db = mongoose.connection
var sessionStore = new MongoStore({mongoose_connection: db});

Using RedisStore <---- EDIT: this works after installing redis---->

var express = require('express');
var RedisStore = require('connect-redis')(express);
var sessionStore = new RedisStore();

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Changes for express 3x to 4x migration

Redis Store

var session = require('express-session');
var RedisStore = require('connect-redis')(session);
var sessionStore = new RedisStore(options);

app.use(session({
    store: sessionStore,
    secret: 'keyboard cat'
}));

To use the RedisStore one needs first to install redis and start the redis-server. This is how to do it on ubuntu,

To install:

1. sudo apt-get update
2. sudo apt-get install redis-server

To restart the redis-server

1. sudo service redis-server restart