Add enum capabilities to your active record objects

active_record_enums.rb

# this adds enum capibilities to an active record model
# http://jeffkreeftmeijer.com/2011/microgems-five-minute-rubygems/
module ActiveRecordEnum
  def self.included(base)
    base.extend(ClassMethods)
  end

  module ClassMethods
    # how to define an enum on a model
    # pass :prefix => true to prefix the ? methods with attribute name
    def enum(attribute, choices, options = {})
      prefix = options[:prefix] ? "#{attribute}_" : ''

      # add an 'attributes' method
      define_singleton_method(:"#{attribute.to_s.pluralize}") { choices }

      # add 'choice?' methods
      choices.each do |choice|
        define_method(:"#{prefix}#{choice}?") { send(attribute) == choice }
      end
    end
  end
end
ActiveRecord::Base.send(:include, ActiveRecordEnum)