title: Absolute URL's with link_to...Ruby on Rails
body: <p>Is it possible to generate absolute URL's in rails using link to? [NOTE: THIS IS IN A MAILER]</p>
  
  <p>I tried to do:</p>
  
  <pre><code>&lt;%= link_to root_url, root_url%&gt;
  </code></pre>
  
  <p>But I get a runtime error:</p>
  
  <p>*Missing host to link to! Please provide :host parameter or set default_url_options[:host]*</p>
  
  <p>I need this to be dynamic because the application will run on a wildcard domain (*.domain.com)</p>