The docs for instrumenting your Sinatra app with New Relic on Heroku are either wrong or a bit sparse. Its actually very simple.

1. Add the 'newrelic_rpm' gem to either your .gems or Gemfile
2. require the 'rpm' library when in production configure :production do require 'newrelic_rpm' end
3. add the heroku new_relic addon heroku addons:add newrelic:bronze