title: How do I use ES6 (ES2015) in a ruby on rails app?
body: <p>I have a 4.2 rails app and am considering slowly converting the JS to ES6. Right now I'm using the standard rails manifest file from the asset pipeline to pre-process my js. </p>
  
  <p>I'm not sure how to go about starting to use ES6 (adding a transpile step) in my rails app. </p>
  
  <p>Is there a built-in method, or a recommended tool or workflow?</p>