CarrierWave & MongoMapper not save images

[Goodkowski]

I use MongoMapper, CarrierWave and MongoMapper ORM for Carrierwave.

But, CarrierWave not save images and path. I don't know where's problem. In Sub model everything work fine.

Post model (models/post.rb)

 require "carrierwave/orm/mongomapper"

class Post
    include MongoMapper::Document

    before_create :store_user_data

    key :name, String
    key :username, String
    key :description, String
    key :thumb, String

    many :subs
    belongs_to :user

    mount_uploader :thumb, IntromgUploader

    private
        def store_user_data
            self.username = self.user.name
        end
end

MongoMapper ORM for Carrierwave (lib/carrierwave/orm/mongomapper) 

# encoding: utf-8

require 'mongo_mapper'
require 'carrierwave/validations/active_model'

module CarrierWave
  module MongoMapper
    include CarrierWave::Mount
    ##
    # See +CarrierWave::Mount#mount_uploader+ for documentation
    #
    def mount_uploader(column, uploader, options={}, &block)
      options[:mount_on] ||= "#{column}_filename"
      key options[:mount_on]

      super

      alias_method :read_uploader, :read_attribute
      alias_method :write_uploader, :write_attribute

      include CarrierWave::Validations::ActiveModel

      validates_integrity_of  column if uploader_option(column.to_sym, :validate_integrity)
      validates_processing_of column if uploader_option(column.to_sym, :validate_processing)

      after_save "store_#{column}!".to_sym
      before_save "write_#{column}_identifier".to_sym
      after_destroy "remove_#{column}!".to_sym
    end
  end
end

MongoMapper::Plugins::Rails::ClassMethods.send(:include, CarrierWave::MongoMapper)

Intromg uploader (app/uploaders/intromg_uploader.rb)

require "carrierwave/orm/mongomapper"

class Post
    include MongoMapper::Document

    before_create :store_user_data

    key :name, String
    key :username, String
    key :description, String
    key :thumb, String

    many :subs
    belongs_to :user

    mount_uploader :thumb, IntromgUploader

    private
        def store_user_data
            self.username = self.user.name
        end
end