如何在Rails中为Mechanize设置自定义用户代理

I know you have a set of pre-defined aliases you can use by setting agent.user_agent_alias = 'Linux Mozilla' for instance, but what if I want to set my own user agent, as I'm writing a web crawler and want to identify it, for the sites I'm indexing's sake. Just like Googlebot.I know you have a set of pre-defined aliases yo