def run_callback(method, *args)
      case method
      when Symbol
        send(method, *args)
      when Proc
        instance_exec(*args, &method)
      else
        raise "Please register with callbacks using a symbol or a block/proc."
      end
    end
def run_callback(method, *args)
      case method
      when Symbol
        send(method, *args)
      when Proc
        instance_exec(*args, &method)
      else
        raise "Please register with callbacks using a symbol or a block/proc."
      end
    end
Simple callback system. Implements before and after callbacks for
 use within the controllers.

 We didn't use the ActiveSupport callbacks because they do not support
 passing in any arbitrary object into the callback method (which we
 need to do)