支持，see https://github.com/huacnlee/ruby-china/blob/master/app/models/comment.rb

#1 楼 @huobazi 我高了半天没成功。

#2 楼 @metal

class Company
  include Mongoid::Document
  has_many :posts, as: :postable
end

class Person
  include Mongoid::Document
  has_many :posts, as: :postable
end

class Post
  include Mongoid::Document
  belongs_to :postable, polymorphic: true
end

mongoid.org 上的代码，poly 还需要一个表示能力的文档，不过是虚的，一般叫 xxxxable

children 标示为:polymorphic => true

parent 用:as => xxxxable

#3 楼 @willmouse 3Q