[Rails] 中間テーブルで並び順を制御したい時におすすめのTips

class CreateUserTags < ActiveRecord::Migration[7.0]
  def change
    create_table :user_tags do |t|
      t.references :user, null: false, foreign_key: true
      t.references :tag, null: false, foreign_key: true
      t.integer :position, null: false, default: 0

      t.timestamps
    end
  end
end

class UserTag < ApplicationRecord
  belongs_to :user
  belongs_to :tag

  scope :ordered, -> { order(position: :asc) }
end

class User < ApplicationRecord
  has_many :user_tags, -> { ordered }, dependent: :destroy
  has_many :tags, through: :user_tags
end

class Tag < ApplicationRecord
  has_many :user_tags, -> { ordered }, dependent: :destroy
  has_many :users, through: :user_tags
end