SMS-70 Adding New Relic monitoring

#### What's this PR do?
Adds New Relic monitoring to our app in production. I've also just added the NEWRELIC_LICENSE_KEY environment variable to our Nodejitsu env.

#### Any background context?
* Raised priority on getting this done sooner so that we can try to better debug errors we're seeing on production.
* Basically just followed this to hook it up: http://newrelic.com/nodejs

#### What are the relevant tickets?
SMS-70

cc: @mshmsh5000 Just a heads up that this app should start showing up in New Relic too.