code for blog post

serializable_hash.rb

class User  
alias_method :super_serializable_hash, :serializable_hash
  def serializable_hash(options = {})
   options.merge! {
      :only => self.attributes.keys.map(&:to_sym) - 
                  (self.class.deprecated_attributes ||
                  []).map(&:to_sym)
    }
    super_serializable_hash(options)
  end
end