module InheritableClassAttributes::ClassMethods

def cattr_inheritable_writer(*symbols)
  symbols.each do |symbol|
    self.inheritable_cattr_writers << symbol
    self.module_eval %{
      def self.#{symbol}=(value)
        @#{symbol} = value
      end
    }
  end
  self.inheritable_cattr_writers.uniq!
end