devise的使用的中文教程

http://cn.asciicasts.com/episodes/210-customizing-devise
http://zool.iteye.com/blog/712836

将后台用rails_admin重建

http://www.hupengxing.com/blogs/87-%E5%B0%86%E5%90%8E%E5%8F%B0%E7%94%A8rails_admin%E9%87%8D%E5%BB%BA
undler could not find compatible versions for gem "rails":
  In Gemfile:
    rails (= 3.0.9)

    rails_admin depends on
      rails (3.1.0.rc6)