make_attr.rb

#!/usr/bin/env ruby
# encoding: utf-8

class Hash
  def make_attr
    each_pair do |key, value|
      self.class.send :define_method, key.to_s, Proc.new { value }
    end
  end

  def attr_tracker
    self.class.send :define_method, '[]=', Proc.new { |key, value|
      update key => value
      make_attr
    }
  end
end