app/views/admin/orders/_breadcrumb.html.erb
<ol class="breadcrumb">
<li><%= link_to "Orders", admin_orders_path %></li>
<% if current_page == "show" %>
<li class="active">Order #<%= @order.id.to_s %></li>
<% elsif current_page == "edit" %>
<li><%= link_to "Order #"+@order.id.to_s, admin_order_path(@order) %></li>
<li class="active">Edit</li>
<% end %>
</ol>