two major fix for site setting and bulletin controller

app/controllers/admin/pages_controller.rb

@@ -21,11 +21,15 @@ class Admin::PagesController < Admin::ItemsController
   end
 
   def update
-    if params[:page][:category][0] == ""
-      params[:page][:category] = []
+    if params[:page][:category]
+      if params[:page][:category][0] == ""
+        params[:page][:category] = []
+      end
     end
-    if params[:page][:tag][0] == ""
-      params[:page][:tag] = []
+    if params[:page][:tag]
+      if params[:page][:tag][0] == ""
+        params[:page][:tag] = []
+      end
     end
     @item = Page.find(params[:id])
     if @item.module_app && @item.module_app.key == 'page_content' && @item.page_contexts.blank?