title: wp_nav_menu - add class on UL
body: <p>I am learning <code>wordpress</code> together with <code>bootstrap</code> and somehow I can't add <code>class</code> on <code>UL</code> tag.</p>
  <p>In the screenshot, I want to add class <code>nav nav-tabs</code> on <code>UL</code> but it was added on parent <code>div</code></p>
  <pre class="lang-php prettyprint-override"><code>$defaults = array(
    'menu_class'=&gt; 'nav nav-tabs',        
  );
  
  wp_nav_menu( $defaults ); 
  </code></pre>
  <p>Inspected element:</p>
  <p><img src="https://i.stack.imgur.com/nSZXy.png" alt="enter image description here" /></p>
  <p>Referrence:<br />
  <a href="http://codex.wordpress.org/Function_Reference/wp_nav_menu" rel="nofollow noreferrer">http://codex.wordpress.org/Function_Reference/wp_nav_menu</a></p>