app/views/shared/_menu.html.erb
<div id="menu">
<p class="menu">
<% if signed_in? -%>
<%= link_to t(:folders), folders_path %>
<% if current_user.member_of_admins? -%>
<%= link_to t(:users), users_path %>
<%= link_to t(:groups), groups_path %>
<%= link_to t(:shared_files), share_links_path %>
<% end -%>
<% end -%>
</p>
</div>