fix bug

app/controllers/zips_controller.rb

@@ -40,12 +40,12 @@ class ZipsController < ApplicationController
   def get_exercise
     ActiveRecord::Base.transaction do
       begin
-        @exercise = Exercise.find_by(id:params[:exercise_id]).includes(:exercise_users)
+        @exercise = Exercise.includes(:exercise_users).find_by(id:params[:exercise_id])
         group_id = params[:exercise_group_id]
         if @exercise.blank?
           normal_status(-1,"试卷不存在")
         else
-          @course = @exercise.course.includes(:course_members)
+          @course = @exercise.course
 
           default_ex_users = @exercise.all_exercise_users(current_user.id).exercise_user_committed
           default_ex_users_size = default_ex_users.size