def upload(&block)
      @source.files.each do |key, file|
        object = @target.files.create({
          :key => key,
          :body => file,
          :public => true,
          :cache_control => 'max-age=0' # Disable cache on S3 so that future sharts are visible if folks web browsers.
        })
        block.call file, object
      end
    end
def upload(&block)
      @source.files.each do |key, file|
        object = @target.files.create({
          :key => key,
          :body => file,
          :public => true,
          :cache_control => 'max-age=0' # Disable cache on S3 so that future sharts are visible if folks web browsers.
        })
        block.call file, object
      end
    end
Upload files from target to the source.