class MigrateDisciplinePosition < ActiveRecord::Migration[5.2]
  def change
    Discipline.all.each_with_index do |discipline, i|
      discipline.update_column("position", i + 1)

      discipline.sub_disciplines.each_with_index do |sub, j|
        sub.update_column("position", j + 1)

        sub.tag_disciplines.each_with_index do |tag, k|
          tag.update_column("position", k + 1)
        end
      end
    end
  end
end