我是铁杆新手。 我按照本页面的教程尝试生成一个hello world页面：
http://arubystory.blogspot.com/2013/11/tutorial-saying-hello-world-with-ruby.html
然而，在我完成所有步骤并完成所有步骤并启动服务器后，我收到以下错误：有人可以帮忙吗？提前谢谢！
Showing /home/ec2-user/testApp4/app/views/layouts/application.html.erb where line #6 raised:
undefined method `close!' for nil:NilClass
(in /home/ec2-user/.rvm/gems/ruby-2.1.2/gems/turbolinks-2.2.2/lib/assets/javascripts/turbolinks.js.coffee)
Extracted source (around line #6):
<head>
<title>TestApp4</title>
<%= stylesheet_link_tag 'application', media: 'all', 'data-turbolinks-track' => true %>
<%= javascript_include_tag 'application', 'data-turbolinks-track' => true %>
<%= csrf_meta_tags %>
</head>
<body>