Xvincentx/redis addon

[Trello Card](https://trello.com/c/nUdZsuq4/2087-set-up-persisent-sessions-on-protected-s3)

## Do not merge, test required
### Heroku requires credit card verification. I do not own a credit card, cannot test on line!

I've used [connect-redis](https://www.npmjs.org/package/connect-redis) to store session if env variable has been set.