app/views/shared/_header.html.erb
<nav class="navbar navbar-default navbar-fixed-top">
<div class="container">
<div class="navbar-header"><%= link_to 'mtdevise', account_root_path, class: 'navbar-brand' %>
</div>
<div class="collapse navbar-collapse">
<ul class="dropdown-menu nav navbar-nav navbar-right">
<li>
<a aria-expanded="false" class="dropdown-toggle" data-toggle="dropdown" href="#" role="button">Settings<span class="caret"></span></a>
<%- if user_signed_in? %>
<ul class="dropdown-menu" role="menu">
<li>Signed in as <%= current_user.email %></li>
<li class="divider"></li>
<li><%= link_to 'Log out', destroy_user_session_path, method: :delete %></li>
</ul>
<% end %>
</li>
</ul>
</div>
</div>
</nav>