class MigrateCourseGroupPosition < ActiveRecord::Migration[5.2]
  def change
    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|
        group.update_attribute(:position, position)
        position += 1
      end
    end
  end
end