title: How to set custom user-agent for Mechanize in Rails
body: <p>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.</p>
  
  <p>There seems to be a user_agent method, but I can't seem to find any documentation about it's function.</p>