需要帮助，新手整合 Carrierwave 和 Mongoid 时出错：

NoMethodError (undefined method `validate_integrity' for :ImageUploader:Symbol):
  app/models/picture.rb:5:in `<class:Picture>'
  app/models/picture.rb:1:in `<top (required)>'
  app/controllers/uea_controller.rb:12:in `imageup'

bundle show:

Gems included by the bundle:
  * actionmailer (3.2.11)
  * actionpack (3.2.11)
  * activemodel (3.2.11)
  * activerecord (3.2.11)
  * activeresource (3.2.11)
  * activesupport (3.2.11)
  * arel (3.0.2)
  * builder (3.0.4)
  * bundler (1.2.3)
  * carrierwave (0.8.0)
  * carrierwave-mongoid (0.6.0)
  * coffee-rails (3.2.2)
  * coffee-script (2.2.0)
  * coffee-script-source (1.6.2)
  * erubis (2.7.0)
  * execjs (1.4.0)
  * hike (1.2.2)
  * i18n (0.6.4)
  * journey (1.0.4)
  * jquery-rails (2.2.1)
  * json (1.8.0)
  * mail (2.4.4)
  * mime-types (1.23)
  * mongoid (3.1.4)
  * mongoid-grid_fs (1.8.0)
  * moped (1.5.0)
  * multi_json (1.7.3)
  * origin (1.1.0)
  * polyglot (0.3.3)
  * rack (1.4.5)
  * rack-cache (1.2)
  * rack-ssl (1.3.3)
  * rack-test (0.6.2)
  * rails (3.2.11)
  * railties (3.2.11)
  * rake (10.0.4)
  * rdoc (3.12.2)
  * rmagick (2.13.2)
  * sass (3.2.9)
  * sass-rails (3.2.6)
  * sprockets (2.2.2)
  * thor (0.18.1)
  * tilt (1.4.1)
  * treetop (1.4.12)
  * tzinfo (0.3.37)
  * uglifier (2.1.1)

Controller Class:

class UeaController < ApplicationController
    respond_to :html, :json
    def showimage
    end

   def imageup
        @picture = Picture.new params[:upfile]
        if @picture.save
            @msg = {:url=>@picture.image.url(:original),:title=>params[:pictitle],:original=>params[:fileName],:state=>'SUCCESS'}
        else
            @msg = {:url=>'',:title=>'',:original=>'',:state=>'文件保存时出错'}
        end
        respond_with @msg
#render :json=>msg.to_json
    end

    def imageManager
    end
end

Model Class:

class Picture
  include Mongoid::Document
  attr_accessible :image
  field :image, type: String
  mount_uploader :image, :ImageUploader
end

Uploader Class:

class ImageUploader < CarrierWave::Uploader::Base
  storage :file

  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end
end