照着教程搭建了 Rails 的环境，能够正常运行，但是会但一个警告，如下： SECURITY WARNING: No secret option provided to Rack::Session::Cookie. This poses a security threat. It is strongly recommended that you provide a secret to prevent exploits that may be possible from crafted cookies. This will not be supported in future versions of Rack, and future versions will even invalidate your existing user cookies.
Called from: /home/soledad/.rvm/gems/ruby-1.9.3-p362/gems/actionpack-3.2.10/lib/action_dispatch/middleware/session/abstract_store.rb:28:in `initialize'.
服务器是正常允许的，rails 是 3.2.10 版本，想请教一下，是不是配置有些什么问题？
stackoverflow已经有讨论，无需修正，或者硬要修的话，修改/home/soledad/.rvm/gems/ruby-1.9.3-p327/gems/actionpack-3.2.10/lib/action_dispatch/middleware/session 目录下的 abstract_store.rb，插一行即可：
module Compatibility
def initialize(app, options = {})
options[:key] ||= '_session_id'
options[:secret] ||= Rails.application.config.secret_token # insert this line, only a temp solution
super
end
