STI example.

sti.rb

class Vehicle < ActiveRecord::Base
  attr_accessor :direction
  validates :name, presence: true
end

class Car < Vehicle
  def turn_wheel(direction)
    @direction = direction
    puts "wheel was turned to the #{direction}"
  end
end

class Bike < Vehicle
  def turn_handlebar(direction)
    @direction = direction
    puts "handlebar was turned to the #{direction}"
  end
end