Module方法调用好不好
以前说，用module给class加singleton方法，和extend到类include到类的instance
现在看看这个

module Prober  class << self    def probe_invoke(type, data = {})      p = Probe.new({:probe_type => type.to_s,          :data => data.to_json, :probe_status => 0, :retries => 0})      p.save    end    # more module instance methods ...  endend