mongoid和嵌入式文档的问题

Question

我无法解决删除嵌入式文档的问题 - 即使发现父级和嵌入式文档很难发生也是如此。我已经在Stackoverflow和Github问题上搜索了其他问题，但没有一个建议有效。

以下是负责删除嵌入式文档的代码（使用最新的sinatra，mongo和mongoid gems）：

delete '/api/items/:id/notes/:note_id' do
    owner_email = session[:logged_user].email
    id = params[:id]
    item = ToDoItem.by_user(owner_email).find(id)
    if item.nil?
        halt 404, 'Item not found'
    else
        note_id = params[:note_id]
        note = item.notes.find(note_id)
        # logger.info BSON::ObjectId(note_id).to_s
        # logger.info note.to_json

        note.destroy      
        item.save!
        item.reload
        { :success => true }.to_json
    end
end

这是模特：

class ToDoItem
    include Mongoid::Document
    include Mongoid::Timestamps
    include Mongoid::Attributes::Dynamic

    field :sort_order,  type: Integer,  default: 1
    field :name,        type: String
    field :completed,   type: Boolean,  default: false
    field :owner_email, type: String
    field :categories,  type: Array,    default: ['general']
    field :id,          type: String
    embeds_many :notes

    def self.by_user(email)
        where(owner_email: email)
    end

    def self.by_category(category)
        where(categories: category)
    end

    def self.by_completed
        where(completed: true)
    end

    def id
        BSON::ObjectId(_id).to_s
    end
end

 class Note
  include Mongoid::Document
  include Mongoid::Timestamps
  field :text, type: String
  field :id,   type: String

  def id
    BSON::ObjectId(_id).to_s
   end

  embedded_in :todoitem
 end