.htaccess subdomain argument not accessible in query string

I have written the following rules in .htaccess

RewriteCond %{HTTP_HOST} ^([^\.]+)\.domain\.com 

RewriteCond %1 !^www$ [NC]

RewriteCond %{REQUEST_URI} ^/news/news-details\.php$

RewriteRule (.*) news.php?div=%1

Redirect "myapp.com" to "www.myapp.com" in rails without using htaccess?

Using Morph Labs' Appspace to deploy a site means no automated way to redirect 'myapp.com' to 'www.myapp.com' (and no access to .htacess).