Add task to flatten category and tag for page and page_part

lib/tasks/migrate.rake

@@ -209,6 +209,19 @@ namespace :migrate do
     end
   end
 
+  task :flatten_category_and_tag => :environment do
+    [Page,PagePart].each do |obj|
+      obj.all.each do |pp|
+        unless pp.category.blank?
+          pp.update_attribute(:category, pp.category.flatten)
+        end
+        unless pp.tag.blank?
+          pp.update_attribute(:tag, pp.tag.flatten)
+        end
+      end
+    end
+  end
+
   task :clean_parts => :environment do
     PagePart.where(widget_style: /\d/, kind: 'module_widget').each{|part| part.update_attributes({kind: 'text', widget_style: nil, widget_field: nil})}
     PagePart.where(widget_style: /\d/).each{|part| part.update_attributes({widget_style: nil, widget_field: nil})}