<p>When using a subdomain and trying to view anything related to current_user. user is sent to a new session page, the page shows the session is created and gives the option to logout. I can use no subdomain and it works fine.</p>

Set it in your environment.rb (or environments/*.rb if you'll use different domains for each environment):
```
```
ActionController::CgiRequest::DEFAULT_SESSION_OPTIONS.update( :session_domain => '.domain.com')
```
```