ActiveRecord basics boilerplate

This is a minimalist implementation of ActiveRecord with one Restaurant model to live-code a demo for @LeWagon students, part of Karr examples

• clone the repo
• run rake db:create to create your db
• run your migrations with rake db:migrate

Now you can play with the Restaurant model:

$ irb
irb> load "config/application.rb"
irb> restaurant = Restaurant.new(name: "La Tour d'Argent", address: "15 Quai de la Tournelle, 75005 Paris")
irb> restaurant.persisted?
     # => false
irb> restaurant.id
     # => nil
irb> restaurant.save
irb> restaurant.id
     # => 1