bug#2901:课程讨论区：从个人主页到了如下页面，但从课程论坛就再也进不到这个页面了

MessagesController#show跳转到BoardsController#index

app/controllers/messages_controller.rb

@@ -37,6 +37,14 @@ class MessagesController < ApplicationController
 
   # Show a topic and its replies
   def show
+    if @course
+      topic_id = params[:r]?params[:r]:params[:id]
+      parent_id = params[:id]
+      url = course_boards_path(@course,:topic_id => topic_id,:parent_id=>parent_id);
+      redirect_to url
+      return;
+    end
+
     @isReply = true
     page = params[:page]
     # Find the page of the requested reply