Barcode Generating With Label On Canvas by using Barby gem

********UNDEFINED METHOD REGISTER ERROR IN THE FALLOWING CODE *******
Hi all,

I am trying to generate barcode(including its name as label at the
bottom of barcode image for easy understand with out scanning by barcode
scanner).

For this I am Using barby, chuncky_png, rmagick gems.
I am using the fallowing code to generate label at bottom of image by
using rmagick gem:

gem ‘barby’
gem ‘chunky_png’
gem ‘rmagick’
require ‘rubygems’
require ‘barby’
require ‘barby/outputter/rmagick_outputter’
require ‘barby/barcode/code_128’
require ‘barby/outputter/prawn_outputter’
require ‘pdf/writer’

module Barby
class RmBarcode < ActiveRecord::Base
register :to_image_with_data
def to_image_with_data
#Make canvas bigger
canvas = Magick::ImageList.new
canvas.new_image(full_width , full_height + 10)
canvas << to_image
canvas = canvas.flatten_images
#Make the text
text = Magick::Draw.new
text.font_family = ‘helvetica’
text.pointsize = 14
text.gravity = Magick::SouthGravity
text.annotate(canvas , 0,0,0,0, barcode.data)
canvas
end
end
end
barcode = Barby::Code128B.new(‘Barcode Code Here’)
barcode.to_image_with_data.write(‘barcode_2.png’)

but I am getting the fallowing error:

undefined method `register’ for #Class:0x4d08ef0

yy??

any information that is valuable to me.
thanks in advance…