Virtual attributes #1

virtual_attributes.rb

module VirtualAttributes
  extend ActiveSupport::Concern

  module ClassMethods
    def attr_virtual(*attrs)
      options = attrs.extract_options!

      attrs.each do |attr|
        class_eval do
          send("attr_accessor", attr)
        end

        columns_hash[attr] = ActiveRecord::ConnectionAdapters::Column.new(attr, nil, options[:klass])
      end
    end
  end
end