Bare minimum rails project to experiment on models

restaurant.rb

# Instead of loading all of Rails, load the
# particular Rails dependencies we need
require 'sqlite3'
require 'active_record'
require 'pry'

# Set up a database that resides in RAM
ActiveRecord::Base.establish_connection(
  adapter: 'sqlite3',
  database: ':memory:'
)

# Set up database tables and columns
ActiveRecord::Schema.define do
  create_table "bookings", force: :cascade do |t|
    t.string   "name"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.references :order, polymorphic: true, index: true, null: false
  end

  create_table "pickup_orders", force: :cascade do |t|
    t.string   "notes"
    t.string   "fax"
    t.string   "pickup_time"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "delivery_orders", force: :cascade do |t|
    t.string   "notes"
    t.string   "home_address"
    t.string   "delivery_time"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end
end

# Set up model classes
class ApplicationRecord < ActiveRecord::Base
  self.abstract_class = true
end
class Booking < ApplicationRecord
  belongs_to :order, polymorphic: true
end

class PickupOrder < ApplicationRecord
  has_many :bookings, as: :order, dependent: :destroy, inverse_of: :order
end

class DeliveryOrder < ApplicationRecord
  has_many :bookings, as: :order, dependent: :destroy, inverse_of: :order
end

# Try everything out!
booking = Booking.new
booking.name = "Yummy food!"
booking.order = PickupOrder.new(notes: 'need it really tasty', pickup_time: 'in 2 hours')
booking.save

booking = Booking.new
booking.name = "Spicy food!"
booking.order = DeliveryOrder.new(notes: 'need it really spicy', delivery_time: 'in 2 hours')
booking.save
binding.pry
p Booking.count