nav.php

<nav class="navbar navbar-default">
  <div class="container-fluid">
    <div class="navbar-header">
      <a class="navbar-brand" href="/index.php/all_tweets">
        <img class="home-icon" alt="Twitter" src="../../img/twitter.png">
      </a>
    </div>
    <ul class="nav navbar-nav">
      <li><a href="/index.php/all_tweets">Feed</a></li>
      <li><a href="/index.php/user_tweets">Profile</a></li>
    </ul>
    <form class="logout form-inline my-2 my-lg-0" action="/index.php/user_tweets/logout" method="post">
      <button class="btn btn-primary my-2 my-sm-0" type="submit">Logout</button>
    </form>
  </div>
</nav>