I would use the new domain and do a permanent redirect of the old site to the new one. The type of redirect is caled a 301.
Since you are writing about Linux Casinos I am wondering if you are using an Apache webserver? If so and you have .htaccess enabled and in use, then you can add this to your .htaccess file (usually found in the root of your webserver’s public html location):
Redirect 301 / http://newdomain.com
Let me know if you need more help with this.