app/views/admin/users/_breadcrumb.html.erb
<ol class="breadcrumb">
<li><%= link_to "Admins", admin_users_path %></li>
<% if current_page == "show" %>
<li class="active">Admin #<%= @admin.id.to_s %></li>
<% elsif current_page == "new" %>
<li class="active">New</li>
<% elsif current_page == "edit" %>
<li><%= link_to "Admin #"+@admin.id.to_s, admin_user_path(@admin) %></li>
<li class="active">Edit</li>
<% end %>
</ol>