change migration exercsie

db/migrate/20190822022306_add_exercise_user_update.rb

@@ -1,7 +1,7 @@
 class AddExerciseUserUpdate < ActiveRecord::Migration[5.2]
   include ExercisesHelper
   def change
-    exs = Exercise.all.is_exercise_published.where("published_time > ?",(Time.now - 2.months)).includes(:exercise_questions,:exercise_users)
+    exs = Exercise.all.is_exercise_published.where("publish_time > ?",(Time.now - 2.months)).includes(:exercise_questions,:exercise_users)
     exs.each do |ex|
       ex_users = ex.exercise_users.exercise_user_committed.where("end_at is not null and end_at > ?",(Time.now - 2.months))
       if ex_users.present?