title: How do you add an icon to a button_tag using HAML?
body: <p>I am having trouble trying to make a play button using HAML. </p>
  
  <pre><code> =button_tag clue_path(@question), class: "btn btn-lg glyphicon glyphicon-play" 
  </code></pre>
  
  <p>Results in html</p>
  
  <pre><code>&lt;button&gt;&lt;icon class:"glyphicon glyphicon-play"&gt;/question/1/clue&lt;/i&gt;&lt;/button&gt;
  </code></pre>
  
  <p>It should be</p>
  
  <pre><code>&lt;button&gt;&lt;icon class: "glyphicon glyphicon-play"&gt;&lt;/i&gt;&lt;/button&gt;
  </code></pre>
  
  <p>I'm super close to resolving it. What am I missing?</p>