DistroPropaganda/code/rails40/depot_k/db/migrate/20121130000006_add_price_to_line_item.rb

#---
# Excerpted from "Agile Web Development with Rails",
# published by The Pragmatic Bookshelf.
# Copyrights apply to this code. It may not be used to create training material,
# courses, books, articles, and the like. Contact us if you are in doubt.
# We make no guarantees that this code is fit for any purpose.
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#---
class AddPriceToLineItem < ActiveRecord::Migration
  def change
    add_column :line_items, :price, :decimal
    LineItem.all.each do |li|
      li.price = li.product.price
    end
  end
end