在Rails中确认电子邮件，而不使用任何现有的身份验证gem /插件

I'm working on this alerting service in Rails. And really, all I need to do is, when a user signs up, send a confirmation email to the user. And upon confirmation from the user, activate the user. I tried playing around with Matt Hooks' Authlogic email activation tutorial, but its really leading nowhere. So , any ideas how I can do this with minimum fuss ? Thanks ! I'm working on this alerting service in Rails.