class Model
  def initialize(hash={})
    @attributes = hash
  end

  def read_attribute_for_serialization(name)
    @attributes[name]
  end

  def id
    object_id
  end
end


###
## Models
###
class User < Model
  def profile
    @profile ||= Profile.new(name: 'N1', description: 'D1')
  end
end

class Profile < Model
end


###
## Serializers
###
class UserSerializer < ActiveModel::Serializer
  attributes :name, :email

  has_one :profile
end

class ProfileSerializer < ActiveModel::Serializer
  def description
    description = object.read_attribute_for_serialization(:description)
    scope ? "#{description} - #{scope}" : description
  end

  attributes :name, :description
end