custom_enum.rb

require 'active_support'

module CustomEnum
  extend ActiveSupport::Concern

  def enum(name, values, attr_name:)
    attr = name
    attr = attr_name if attr_name.present?

    define_method("#{name}") { values.key(read_attribute(attr)) }
    define_method("#{name}=") { |s| write_attribute(attr, values[s]) }
  end
end

ActiveRecord::Base.send :extend, CustomEnum