def process_opts(options)
      if options.key?(:only)
        options[:event] = options.delete(:only)
      elsif options.key?(:except)
        options[:event] = [:set_user, :authentication] - Array(options.delete(:except))
      end
      options
    end
def process_opts(options)
      if options.key?(:only)
        options[:event] = options.delete(:only)
      elsif options.key?(:except)
        options[:event] = [:set_user, :authentication] - Array(options.delete(:except))
      end
      options
    end
set event: to run callback on based on options