title: Speed up deployment on Heroku
body: <p>Heroku is great.  But every time I deploy, Heroku seems to like to redownload and rebuild all the packages.  With <code>socket.io</code> and <code>mailparser</code> this is taking around 3 minutes.</p>
  
  <p>Is there a way to speed up the deployment process?  Is there a way to tell Heroku that it can cache these items?  Or can I upload prebuilt <code>node_modules</code>?</p>