title: How to manually send a Devise email?
body: <p>I want to manually send a Devise confirmation email to a user of my app. Like this:</p>
  
  <pre><code>u = User.last
  Devise::Mailer.confirmation_instructions u
  </code></pre>
  
  <p>but Devise's <code>confirmation_instructions</code> takes three parameters, the second being a token (according to the documentation) and the third being a Hash. How do I get it in order to be able to send these emails?</p>