问如何在rails 4中构建面包屑

EN

module NavigationHelper
  def ensure_navigation
    @navigation ||= [ { :title => 'Home', :url => '/' } ]
  end

  def navigation_add(title, url)
    ensure_navigation << { :title => title, :url => url }
  end

  def render_navigation
    render :partial => 'navigation', :locals => { :nav => ensure_navigation }
  end
end

  <ol class="breadcrumb">
    <% nav.each do |n| %>
      <% unless n.equal? nav.last %>
        <li><%= link_to n[:title], n[:url] %></li>
      <% else %>
        <li><%= n[:title] %></li>
      <% end %>
    <% end %>
  </ol>

<%= render_navigation %>

<% content_for :title, 'My Page Title' %>
    <% navigation_add @something.anything, '#' %>

def breadcrumb(&block)
    content_tag :ol, { :class => "breadcrumb", :itemprop => "breadcrumb" } do
      block.call
    end
end

def breadcrumb_item(name = nil, url = nil, html_options = {}, &block)
    if name or block
      html_options[:class] = "#{html_options[:class]} active" unless url
      content_tag :li, html_options do
        if block
          block.call name, url
        else
          url ? link_to(name, url) : name
        end
      end
    end
  end

<%= breadcrumb do %>
  <%= breadcrumb_item "index", index_path %>
  <%= breadcrumb_item @user.name %>
<% end %>

<%= render_navigation %>

<% content_for :heading do 'User Detail' end %>

module NavigationHelper
  def navigation_add(title, url)
    nav_list = session['navigation'].present? ? session['navigation'] : []
    nav_list << { 'title' => title, 'url' => url }
    # 1. Take last 3 items only (-1 is last, not -0)
    nav_list = nav_list[-3..-1] if nav_list.length > 3
    # 2. Now, if first is pointing root, remove it
    nav_list.shift if nav_list[0]['url'] == '/'
    # 3. If last one is same as its predecessor, remove it
    nav_list.pop if nav_list.length > 1 && (nav_list[-1]['url'] == nav_list[-2]['url'])

    session['navigation'] = nav_list
  end

  def render_navigation
    render partial: 'shared/navigation', locals: { nav_list: session['navigation'] }
  end
end

<ol class="breadcrumb">
  <li><%= link_to '/' do %>
      <i class="fa fa-home"></i> Home <% end %>
  </li>
  <i class="fa fa-angle-double-right" style="color: #ccc; padding: 0 5px;"></i>

  <% nav_list.each_with_index do |nav, i| %>
    <% if i != nav_list.length-1 %>
      <li><%= link_to nav['title'], nav['url'] %></li>
    <% else %>
      <li class="active"><%= nav['title'] %></li>
    <% end %>
  <% end %>
</ol>