Rails4.0からadd_reference使えるようになってた. rails g migration AddPiyoToHoges piyo:refernces とかすると class AddPiyoToHoges < ActiveRecord::Migration def change add_reference :hoges, :piyo, index: true end end なファイルが出来て rails db:migrate するとdb/schema.rbで create_table "hoges", force: true do |t| t.integer "piyo_id" end add_index "hoges", ["piyo_id"], name: "index_hoges_on_piyo_id", using: :btree みたいになる. 便利. 参考 ad
![add_reference来てた | blog.nomnel.net](https://cdn-ak-scissors.b.st-hatena.com/image/square/fb6c32a7bd4b20415cd09370acc85544f8ee198d/height=288;version=1;width=512/https%3A%2F%2Fblog.nomnel.net%2Fog-images%2Frails-add-reference.png)