resource-aware breadcrumbs

application_helper.rb

class ApplicationHelper
  def breadcrumbs
    result = "".html_safe

    association_chain.each_with_index do |item, index|
     # note that .name works for both classes and objects
     result << link_to(item.name.humanize.titlecase, association_chain[0..index])
     result << " &raquo; ".html_safe
    end

    result << resource.name.humanize.titleize
  end
end

In wich rb file do you have to put this piece of code? in the application_helper or in something else? And is this all the code you need to create a breadcrumb? Nothing in the view like render breadcrumb?