class SeedGenerator < ApplicationRecord
  def self.new_receipt_no
    seed = SeedGenerator.find_by_model("sale")
    new_receipt_no = 0
    if (seed.nil?)
      seed = SeedGenerator.new()
      seed.model = "sale"
      new_receipt_no = seed.next
      seed.save

    else
      current_no = seed.next
      seed.next = seed.next + seed.increase_by
      seed.current = current_no
      seed.save
    end

    return seed.current
  end
end