title: Define Travic CI test code coverage with coveralls (scala)
body: <p>I successfully configured and used Travis CI with combination of Coveralls.io as you can see in <a href="https://github.com/yetu/siren-scala" rel="nofollow">the project</a>. Since this is a open-source project I'd love to define 90% test code coverage threshold. Does anyone know how to define such a threshold in Travis CI with combination of coveralls.io?</p>
  
  <p>Thank you!</p>
  
  <p>Best</p>