class CreateUsefuls < ActiveRecord::Migration[6.0]
  def change
    create_table :usefuls do |t|
      t.bigint :article_id
      t.bigint :user_id
      t.timestamps
      t.index [:article_id, :user_id], unique: true
      t.index :user_id
    end
    add_column :articles, :usefuls_count, :integer, default: 0
  end
end