代码优化

app/controllers/challenges_controller.rb

@@ -160,8 +160,8 @@ class ChallengesController < ApplicationController
 
   def show
     @tab = params[:tab].nil? ? 1 : params[:tab].to_i
-    challenge_num = Challenge.where(shixun_id: @shixun).count
-    @power = current_user.manager_of_shixun?(@shixun) && @shixun.status == 0
+    challenge_num = @shixun.challenges_count
+    @power = @shixun.status == 0 # 之前验证走过了是不是管理员，因此这里只用判断是否发布
     @position = @challenge.position
     if @position < challenge_num
       @next_challenge = Challenge.where(:shixun_id => @shixun, :position => @position + 1).first