class ActiveModel::Validations::InclusionValidator

def check_validity!
   raise ArgumentError, "An object with the method include? is required must be supplied as the " <<
                        ":in option of the configuration hash" unless options[:in].respond_to?(:include?)
end

def validate_each(record, attribute, value)
  included = if options[:in].is_a?(Range)
    options[:in].cover?(value)
  else
    options[:in].include?(value)
  end
  unless included
    record.errors.add(attribute, :inclusion, options.except(:in).merge!(:value => value))
  end
end

def validate_each(record, attribute, value)
  unless options[:in].include?(value)
    record.errors.add(attribute, :inclusion, options.except(:in).merge!(:value => value))
  end
end