Issue with appending stack in an external class

[Jae Hess]

Hey Shoers!

Giving the following code (taken from http://help.shoooes.net)
 class Messenger
   def initialize(stack)
     @stack = stack
   end
   def add(msg)
     @stack.app do
       @stack.append do
         para msg
       end
     end
   end
 end

If I pass in a Shoes stack instance, I am running into an issue where  
after calling @stack.app, @stack is nil when calling append.

Anyone else run into this issue?

Thanks in advance!

Cheers!

Jae