Rails 3 private message plugin

Maybe someone knows a good plugin for private messages? I'm using Rails 3 and Devise as a plug-in for authorization. On github, I found only this plugin, but after installing I get the message:开发者_运维问答 undefined local variable or method `has_private_messages'... While in Rails console I can send messages... I would be grateful for any help...

Restart your Server. They plugin may not have loaded.