title: Add defer attribute to javascript_include_tag Rails
body: <p>Is there some way to add the <code>defer</code> attribute easily using the <code>javascript_include_tag</code> helper in Rails?</p>
  
  <p>I.e., is there some easy way to turn</p>
  
  <p><code>&lt;%= javascript_include_tag "blah.js" %&gt;</code></p>
  
  <p>into </p>
  
  <p><code>&lt;script defer src="blah.js"&gt;&lt;/script&gt;</code></p>