Se você instalar agora o Rich with Rails 4, os caminhos dos ativos serão interrompidos.
Depois de instalar o rich conforme as instruções em:
https://github.com/bastiaanterhorst/rich
Coloque essas linhas em “config / routes.rb”
App::Application.routes.draw do
get "/assets/ckeditor/icons.png", to: redirect("/assets/ckeditor/plugins/icons.png")
get "/ckeditor/:filename.:ext", to: redirect("/assets/ckeditor/%{filename}.%{ext}"), constraints: {filename: /.*/}
get "/ckeditor-contrib/:filename.:ext", to: redirect("/assets/ckeditor-contrib/%{filename}.%{ext}"), constraints: {filename: /.*/}
...
end