有一个 mongo mapper model，定义如下：

class CustomSearchEngine include MongoMapper::EmbeddedDocument key :author_uid, ObjectId, required: true key :category, Integer, required: true key :access, Integer, default: 0, required: true key :voters, Array key :votes, Integer, default: 0 key :current_links, Integer, default: 1 key :history_links, Integer, default: 1

# custom search engine specification one :specification # custom search engine annotations many :annotations

many :comments timestamps!

belongs_to :user

attr_accessible :category, :access, :voters, :votes

end

我在 console 下面，运行 CustomSearchEngine.new，报错：

NameError: uninitialized constant Specifications

这是什么问题？