Adding Spree::Order#reset_digital_links! to ease in handling customer support

Hope to add this as a button to the admin soon.

app/models/spree/order_decorator.rb

@@ -10,9 +10,14 @@ Spree::Order.class_eval do
     false
   end
 
-  # UPGRADE_CHECK this works as of spree 1.2.0
-  # check function for changes on upgrade
+  def reset_digital_links!
+    line_items.select(&:digital?).map(&:digital_links).flatten.each do |digital_link|
+      digital_link.update_column :access_counter, 0
+      digital_link.update_column :created_at, Time.now
+    end
+  end
 
+  # UPGRADE_CHECK this works as of spree 1.2.0. check function for changes on upgrade
   def available_shipping_methods(display_on = nil)
     return [] unless ship_address
     all_methods = Spree::ShippingMethod.all_available(self, display_on)