added new tag batch change model

app/controllers/moderator/tags_controller.rb

@@ -0,0 +1,14 @@
+module Moderator
+  class TagsController < ApplicationController
+    before_filter :moderator_only
+    
+    def edit
+    end
+    
+    def update
+      tag_batch_change = TagBatchChange.new(params[:tag][:predicate], params[:tag][:consequent])
+      tag_batch_change.execute
+      redirect_to edit_moderator_tag_path, :notice => "Posts updated"
+    end
+  end
+end