create_invoice_worker.rb

class CreateInvoiceWorker < IronWorker::Base

  attr_accessor :user_id
  
  def run
    u = User.find(user_id)
    usage = u.get_usage
    invoice = u.create_invoice(usage)
    invoice.save
  end

end

gistfile1.rb

worker = ProcessUsersWorker.new
worker.schedule(:start_at => (Time.current + 1.day).change(:hour => 4), 
                :run_every => 3600 * 24)

process_users_worker.rb

class ProcessUsersWorker < IronWorker::Base

  merge_worker "create_invoice_worker", "CreateInvoiceWorker"

  def run
    users = User.all
    users.each do |u|
      worker = CreateInvoiceWorker.new
      worker.user_id = u.id
      worker.queue
    end
  end

end

S3_worker.rb

class S3Worker < IronWorker::Base
  merge_gem 'aws'

  attr_accessor :image_url, :aws_access, :aws_secret

  File.open('~/image.jpg', 'wb') do |fo|
    fo.write open(image_url).read
  end
  Aws::S3Interface.new(aws_access, aws_secret)
  s3.put("mybucket", 'img.jpg', File.open('~/image.jpg'))
end