animals.rb

# Models
class Animal < ActiveRecord::Base
  parent_model

end

class Dolphin < Animal
  parent_model exposes: [:swim, :chirp]
  child_of :animal

  def swim
    puts "Swooooshhhhhhhh"
  end

  def chirp
    puts "Eh-eh-eh ehh ehhh eh ehh"
  end
end

class BottleNoseDolphin < Dolphin
  child_of :dolphin
end

# Migration

class Animals < ActiveRecord::Migration
  def self.up
    create_table :animals do |t|
      t.integer :heir_id
      t.string :heir_type
      t.boolean :invertebrate
      t.timestamps
    end
  end

  def self.down
    drop_table :animals
  end
end

class Dolphin < ActiveRecord::Migration
  def self.up
    create_table :dolphins do |t|
      t.integer :heir_id
      t.string :heir_type
      t.boolean :smelly
    end
  end

  def self.down
    drop_table :dolphins
  end
end

class BottleNoseDolphins < ActiveRecord::Migration
  def self.up
    create_table :bottle_nose_dolphins do |t|
      t.boolean :evil
    end
  end

  def self.down
    drop_table :bottle_nose_dolphins
  end
end

# Runtime

flippy = BottleNoseDolphin.new
flippy.chirp # Good boy!
flippy.invertebrate = false
flippy.smelly = false
flippy.evil = true
flippy.save