调整

db/migrate/20190309085449_migrate_course_members.rb

@@ -4,7 +4,7 @@ class MigrateCourseMembers < ActiveRecord::Migration[5.2]
 
     Course.find_each do |course|
       position = 1
-      course.course_groups.reorder("CONVERT(course_groups.name USING gbk) COLLATE gbk_chinese_ci ASC").find_each do |group|
+      course.course_groups.reorder("CONVERT(course_groups.name USING gbk) COLLATE gbk_chinese_ci ASC").each do |group|
         group.update_attribute(:position, position)
         position += 1
       end

db/migrate/20190720063520_migrate_course_groups_position.rb

@@ -1,11 +0,0 @@
-class MigrateCourseGroupsPosition < ActiveRecord::Migration[5.2]
-  def change
-    Course.find_each do |course|
-      position = 1
-      course.course_groups.unscoped.reorder("CONVERT(course_groups.name USING gbk) COLLATE gbk_chinese_ci ASC").each do |group|
-        group.update_attribute(:position, position)
-        position += 1
-      end
-    end
-  end
-end