调整

db/migrate/20200114071420_migrate_course_group_member_count.rb

@@ -1,4 +1,8 @@
 class MigrateCourseGroupMemberCount < ActiveRecord::Migration[5.2]
   def change
+    CourseGroup.reset_column_information
+    CourseGroup.find_each do |group|
+      CourseGroup.reset_counters(group.id, :course_members_count)
+    end
   end
 end