title: adding ids, and classes to an image tag in rails
body: <p>I have a rails image tag" </p>
  
  <pre><code>&lt;%= image_tag 'how-it-works.png', {id: 'how-it-works'} %&gt;
  </code></pre>
  
  <p>I would also like to add the bootstrap class <code>img-responsive</code> so the image stays within its container. </p>
  
  <p>How would one do it? </p>
  
  <p>I see a few option on the rails docs but none of them seem to be working: </p>
  
  <pre><code>image_tag("icon")
  # =&gt; &lt;img alt="Icon" src="/assets/icon" /&gt;
  image_tag("icon.png")
  # =&gt; &lt;img alt="Icon" src="/assets/icon.png" /&gt;
  image_tag("icon.png", size: "16x10", alt: "Edit Entry")
  # =&gt; &lt;img src="/assets/icon.png" width="16" height="10" alt="Edit Entry" /&gt;
  image_tag("/icons/icon.gif", size: "16")
  # =&gt; &lt;img src="/icons/icon.gif" width="16" height="16" alt="Icon" /&gt;
  image_tag("/icons/icon.gif", height: '32', width: '32')
  # =&gt; &lt;img alt="Icon" height="32" src="/icons/icon.gif" width="32" /&gt;
  image_tag("/icons/icon.gif", class: "menu_icon")
  # =&gt; &lt;img alt="Icon" class="menu_icon" src="/icons/icon.gif" /&gt;
  image_tag("/icons/icon.gif", data: { title: 'Rails Application' })
  # =&gt; &lt;img data-title="Rails Application" src="/icons/icon.gif" /&gt;
  </code></pre>