MONGOLAB_URI=<Mongo DB URI>
PHANTOMJSCLOUD_KEY=<phantomjscloud.com key>
PRERENDER_HOST=<host that does not redirect http to https, to be used by
phantomjscloud.com>
NODE_ENV=<"development" or "production">
SESSION_SECRET=<session secret>
SENDGRID_USER=<sendgrid.com user>
SENDGRID_PASSWORD=<sendgrid.com password>
MIT