Add newrelic gem

https://www.pivotaltracker.com/story/show/63694920

New Relic
https://addons.heroku.com/newrelic#stark

$ heroku addons:add newrelic:stark

- 1.5 Maximum monthly average dynos
- Platform Plugins. 70+ plugins to monitor your entire app stack from databases to caching, and more
- Histograms and Percentiles. Distribution of response times for all your browser and app transactions
- Alert Policies. The right alerts, to to the right people, via the right channels. 
- Error Detection and Analysis. Drill down into server errors
- Reporting and Optimization. Capacity, Scalability, Long-Term Perf, and SLA reports
- App Monitoring. Snapshot of app health and availability
- Database Analysis and Breakdown. Deep visibility into SQL statements and EXPLAINS.
- Database Performance. Worst performing DB calls
- Real User Analysis and Breakdown. In-depth, page-by-page analysis
- Real User Monitoring. Snapshot of user satisfaction and front-end performance
- Transaction Traces. Code level diagnostics with full stack traces, even across tiers

Installing
https://devcenter.heroku.com/articles/newrelic

$ heroku addons:add newrelic:stark

gem 'newrelic_rpm'

$ curl https://gist.github.com/rwdaigle/2253296/raw/newrelic.yml > config/newrelic.yml

$ heroku config:set NEW_RELIC_APP_NAME="YOUR APP NAME GOES HERE"