# app/uploaders/asset_uploader.rb class AssetUploader < CarrierWave::Uploader::Base  include CarrierWave::MiniMagick   def size_range  0.megabytes..10.megabytes  end   # Override the directory where uploaded files will be stored.  # This is a sensible default for uploaders that are meant to be mounted:  def store_dir  "#uploads/#{model.class.to_s.underscore}/#{model.id}"  end   def extension_white_list  %w[jpg jpeg gif png]  end end