Carrierwave Fog rename file

file_uploader.rb

class FileUploader < CarrierWave::Uploader::Base

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

  def extension_white_list
    %w(pdf)
  end

  def size_range
    0..10.megabytes
  end

  def rename!(new_name)
    new_path = File.join(File.dirname(file.path), new_name)
    old = CarrierWave::SanitizedFile.new file
    new_sf = old.move_to(new_path)
    model.file.cache!(new_sf)
    model.save!
    model
  end

end