class << ActiveRecord::Base
  def acts_as_toggled_date(*attrs)
    attrs.each do |attr|
      method_name = attr.to_s.gsub(/(_at|_on)/, '')
      define_method("#{method_name}?") do
        !self.send(attr.to_s).blank?
      end
      
      define_method(method_name) do
        self.update_attribute(attr, Time.now.utc)
      end
      
      define_method("un#{method_name}") do
        self.update_attribute(attr, '')
      end
    end
  end
end