title: Using Thread.new to send email on rails
body: <p>I've been sending emails on my application (ruby 1.8.7, rails 2.3.2) like this 
  <code>
  Thread.new{UserMailer.deliver_signup_notification(user)} </code></p>
  
  <p>Since ruby use green threads, there's any performance advantage doing this, or I can just use 
  <code>
  UserMailer.deliver_signup_notification(user)
  </code> ?</p>
  
  <p>Thanks</p>