tracks/app/views/todos/_container_items.html.erb

<div id="<%=div_id%>" class="todo_items toggle_target">

  <% cache [settings[:container_name], settings[:show_empty_message]] do %>
    <%= render partial: "todos/container_empty_message", locals: {
      container_id: settings[:container_id], 
      container_name: settings[:container_name],
      show_empty_message: settings[:show_empty_message]} -%>
  <% end -%>

  <%= render(:partial => "todos/todo", :collection => collection, :locals => settings) %>
</div>