Create promotion code per collection for Shopify

gistfile1.txt

# Save your promotion codes in code.csv
require 'capybara'
require 'csv'

session = Capybara::Session.new(:selenium)
session.visit 'https://YOURSHOP.myshopify.com/admin/auth/login'

session.fill_in 'login',    :with => 'YOURLOGIN'
session.fill_in 'password', :with => 'YOURPASSWORD'
session.click_button 'Sign In'

session.click_link 'Promotions'

CSV.read('codes.csv').flatten.each do |code|
  session.click_link 'Add a discount code'

  session.fill_in 'discount[code]',   :with => code
  session.fill_in 'discount[value]',  :with => 'YOUR_DISCOUNT'
  session.select  'collection',       :from => 'discount[applies_to_type]'
  session.select  'YOUR_COLLECTION',  :from => 'discount[applies_to_id]'    

  session.click_link 'infinite number of discount codes'
  session.fill_in 'discount[usage_limit]', :with => '1'

  session.click_button 'Create discount'

  sleep 1
end