tap/app/views/layouts/_header.html.erb

<nav class="navbar navbar-default" role="navigation">
  <div class="container-fluid">
    <!-- Brand and toggle get grouped for better mobile display -->
    <div class="navbar-header">
      <%= link_to "Tab", root_path, class: "navbar-brand" %>
    </div>

    <!-- Collect the nav links, forms, and other content for toggling -->
    <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
      <ul class="nav navbar-nav">
        <li><%= link_to "Overview" , overview_path %> </li> <!-- tijdelijk voor iedereen -->
        <li class="dropdown">
          <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-expanded="false">Products <span class="caret"></span></a>
          <ul class="dropdown-menu" role="menu">
            <li><%= link_to "New product" , new_product_path %></li>
            <li><%= link_to "Index", products_path %></li>
          </ul>
        </li>
        <li class="dropdown">
          <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-expanded="false">Users <span class="caret"></span></a>
          <ul class="dropdown-menu" role="menu">
            <li><%= link_to "New User", new_user_path %></li>
            <li><%= link_to "index" , users_path %></li>
          </ul>
        </li>
      </ul>

      <ul class="nav navbar-nav navbar-center">
        <li class="navbar-text">
          ADMIN NAVBAR
        </li>

      </ul>

      <ul class="nav navbar-nav navbar-right">
        <li class="dropdown">
          <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-expanded="false">Account <span class="caret"></span></a>
          <ul class="dropdown-menu" role="menu">
            <li><a href="#">Profile</a></li>
            <li><a href="#">Update</a></li>
            <li><a href="#">Logout</a></li>
          </ul>
        </li>
      </ul>
    </div><!-- /.navbar-collapse -->
  </div><!-- /.container-fluid -->
</nav>