title: Passing progress messages from server to frontend in Rails 4
body: <p>I'm working on an Rails app which features a custom paperclip processor which accepts video files and manipulates them into various other formats. </p>
  
  <p>As I'm working with video and this process takes a while to complete on the server, I would like to pass information about the status of the processing from the server to the frontend as it's happening. </p>
  
  <p>My question is: what is the best method for getting these messages from my custom paperclip class to my JS without page reload? I'm guessing some kind of event pub/sub system but am unclear on the best method of implementing this. </p>
  
  <p>Sorry if this is a bit of a noob question, been away from Rails for a while!</p>