Update DB schema to store updatable weight on items sold

app/controllers/spree/api/line_items_controller_decorator.rb

@@ -0,0 +1,17 @@
+Spree::Api::LineItemsController.class_eval do
+  after_filter :apply_enterprise_fees, :only => :update
+
+  def apply_enterprise_fees
+    authorize! :read, order
+    order.update_distribution_charge!
+  end
+end
+
+
+#when we update a line item the .update_distribution_charge! is called
+# order.should_receive .update_distribution_charge!
+# check fails when absent
+
+# in order model check that .update_distribution_charge! is properly tested.
+# think through use cases - existing completed order
+# currently likely just used to complete orders so add test case that works on a completed order

db/migrate/20150305004846_add_weight_to_line_items.rb

@@ -0,0 +1,5 @@
+class AddWeightToLineItems < ActiveRecord::Migration
+  def change
+    add_column :spree_line_items, :unit_value, :decimal, :precision => 8, :scale => 2
+  end
+end

db/schema.rb

@@ -549,6 +549,7 @@ ActiveRecord::Schema.define(:version => 20150424025907) do
     t.string   "currency"
     t.decimal  "distribution_fee",     :precision => 10, :scale => 2
     t.string   "shipping_method_name"
+    t.decimal  "unit_value",           :precision => 8,  :scale => 2
   end
 
   add_index "spree_line_items", ["order_id"], :name => "index_line_items_on_order_id"