Add newrelic to gitribution

Minimal changes are also necessary on Heroku or wherever it is at the moment.

1) Get the api key from me

2) Add these configs to the Heroku app:
heroku config:set NEW_RELIC_LICENSE_KEY=licensekeyiwillgiveyou
heroku config:set NEW_RELIC_APP_NAME=gitribution-production
heroku config:set NEW_RELIC_APDEX=<0.010>

3) Pull these changes in.

Cheers!