已修复！

在application.html.erb中，我从以下位置更改了这两行的顺序:

in application.html.erb, I changed the ordering of these two lines from:

<%= stylesheet_link_tag    "application", :media => "all" %>
<%= javascript_include_tag "application" %>

收件人:

<%= javascript_include_tag "application" %>
<%= stylesheet_link_tag    "application", :media => "all" %>

现在可以使用了！我不太确定为什么会有人解释?

Now it works! I'm not quite sure why though, can anybody explain?