app_nav.html.eex

<nav class="navbar navbar-default navbar-fixed-top">
  <div class="container">
    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#primary-nav">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="navbar-brand" href="/">
        <img src="/images/logo.png"/> Mango
      </a>
    </div>
    <div class="collapse navbar-collapse" id="primary-nav">
      <ul class="nav navbar-nav">
        <li><a href="">Link</a></li>
      </ul>
    </div>
  </div>
</nav>