To create a model that references another, use the Ruby on Rails model generator:
$ rails g model wheel car:references
That produces app/models/wheel.rb:
class Wheel < ActiveRecord::Base
belongs_to :car
end
And adds the following migration:
class CreateWheels < ActiveRecord::Migration
def self.up
create_table :wheels do |t|
t.references :car
t.timestamps
end
end
def self.down
drop_table :wheels
end
end
When you run the migration, the following will end up in your db/schema.rb:
$ rake db:migrate
create_table "wheels", :force => true do |t|
t.integer "car_id"
t.datetime "created_at"
t.datetime "updated_at"
end
As for documentation, a starting point for rails generators is Ruby on Rails: A Guide to The Rails Command Line which points you to API Documentation for more about available field types.