Merge branch 'dev_aliyun' of http://bdgit.educoder.net/Hjqreturn/educoder into dev_aliyun

app/controllers/exercises_controller.rb

@@ -1204,7 +1204,7 @@ class ExercisesController < ApplicationController
 
         #筛选/分类,排序
         order = params[:order]
-        if @exercise_users_list.exists? && @exercise_users_list.size > 0
+        if @exercise_users_list.present? && @exercise_users_list.size > 0
           @exercise_users_count = @exercise_users_list.size    #当前显示的全部成员数量
           teacher_reviews = @exercise_users_list.exercise_review
           teacher_unreviews = @exercise_users_list.exercise_unreview