Rails lookup v5 - Migrations to create lookup tables

gistfile1.rb

class CreateCarTypeLookupForCar < ActiveRecord::Migration
  def self.up
    create_table :car_types do |t|
      t.string :name
      t.timestamps #Btw you can remove these, I don't much like them in type tables anyway
    end

    remove_column :cars, :type #Let's assume you have one of those now…
    add_column :cars, :type, :integer #Maybe put not_null constraints here.
  end

  def self.down
    drop_table :car_types
    remove_column :cars, :type
    add_column :cars, :type, :string
  end
end