Complete refactoring of orders-workflow.

OrderResult tables are removed. Data consistency is now possible through new article.price-history (ArticlePrice).
Balancing-workflow needs to be updated.

app/models/article_price.rb

@@ -0,0 +1,29 @@
+# == Schema Information
+# Schema version: 20090120184410
+#
+# Table name: article_prices
+#
+#  id            :integer(4)      not null, primary key
+#  article_id    :integer(4)
+#  price         :decimal(8, 2)   default(0.0), not null
+#  tax           :decimal(8, 2)   default(0.0), not null
+#  deposit       :decimal(8, 2)   default(0.0), not null
+#  unit_quantity :integer(4)
+#  created_at    :datetime
+#
+
+class ArticlePrice < ActiveRecord::Base
+
+  belongs_to :article
+  has_many :order_articles
+
+  # The financial gross, net plus tax and deposit.
+  def gross_price
+    ((price + deposit) * (tax / 100 + 1))
+  end
+
+  # The price for the foodcoop-member.
+  def fc_price
+    (gross_price  * (APP_CONFIG[:price_markup] / 100 + 1))
+  end
+end