title: How to apply class to first button of the div?
body: <p>I have this html and I want to apply class to first button of the DIV.</p>
  
  <pre><code>&lt;div class="button-container"&gt;
   &lt;button class="save" /&gt;
   &lt;button class="reset" /&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I want to add class to the first button.</p>
  
  <p>I want to use jQuery for this solution.</p>