The file db/schema.rb is generated every time you migrate and reflects the latest status of your database schema. You should never edit db/schema.rb by hand since this file is auto-generated from the current state of the database. Instead of editing this file, please
use the migrations feature of Active Record to incrementally modify your database, and then regenerate this schema definition.
Note that this schema.rb definition is the authoritative source for your database schema. If you need to create the application database on another system, you should be using db:schema:load, not running all the migrations from scratch. The latter is a flawed and unsustainable approach (the more migrations you’ll amass, the slower it’ll run and the greater likelihood for issues).
It’s strongly recommended to check this file into your version control system. First of all, it helps to have one definitive schema definition around for reference. Secondly, you can run rake db:schema:load to create your database schema from scratch without
having to run all migrations. That’s especially important considering that as your project evolves, it’s likely that it will become impossible to run migrations all the way through from the start, due to code incompatibilities, such as renaming of classes named explicitly.