Trying to use a decorator with a form object but valid? only seems to return errors for outer level instance. What is the best way to accomplish decoration of FormObjects?

gistfile1.txt

class MyDecorator
  attr_accessor :age
  validates_presence_of :age

  def initialize(subject)
    @subject = subject
  end

  def method_missing(name, *args)
    @subject.send(name, *args)
  end
end

class MyBaseForm
  attr_accessor :name
  validates_presence_of :name
end

test = MyDecorator.new(MyBaseForm.new)
test.valid?
test.errors # Only has age error.