Remove code-duplication of artice price calculation

app/models/article.rb

@@ -1,5 +1,6 @@
 # encoding: utf-8
 class Article < ActiveRecord::Base
+  include PriceCalculation
 
   # @!attribute name
   #   @return [String] Article name
@@ -67,16 +68,6 @@ class Article < ActiveRecord::Base
   before_save :update_price_history
   before_destroy :check_article_in_use
 
-  # The financial gross, net plus tax and deposti
-  def gross_price
-    ((price + deposit) * (tax / 100 + 1)).round(2)
-  end
-
-  # The price for the foodcoop-member.
-  def fc_price
-    (gross_price  * (FoodsoftConfig[:price_markup] / 100 + 1)).round(2)
-  end
-
   # Returns true if article has been updated at least 2 days ago
   def recently_updated
     updated_at > 2.days.ago

app/models/article_price.rb

@@ -1,4 +1,5 @@
 class ArticlePrice < ActiveRecord::Base
+  include PriceCalculation
 
   # @!attribute price
   #   @return [Number] Net price
@@ -27,17 +28,4 @@ class ArticlePrice < ActiveRecord::Base
   validates_numericality_of :unit_quantity, :greater_than => 0
   validates_numericality_of :deposit, :tax
 
-  # Gross price = net price + deposit + tax.
-  # @return [Number] Gross price.
-  # @todo remove code-duplication with Article
-  def gross_price
-    ((price + deposit) * (tax / 100 + 1)).round(2)
-  end
-
-  # @return [Number] Price for the foodcoop-member.
-  # @todo remove code-duplication with Article
-  def fc_price
-    (gross_price  * (FoodsoftConfig[:price_markup] / 100 + 1)).round(2)
-  end
 end
-

app/models/concerns/price_calculation.rb

@@ -0,0 +1,14 @@
+module PriceCalculation
+  extend ActiveSupport::Concern
+
+  # Gross price = net price + deposit + tax.
+  # @return [Number] Gross price.
+  def gross_price
+    ((price + deposit) * (tax / 100 + 1)).round(2)
+  end
+
+  # @return [Number] Price for the foodcoop-member.
+  def fc_price
+    (gross_price  * (FoodsoftConfig[:price_markup] / 100 + 1)).round(2)
+  end
+end