na tom prakticky nic neni, potrebujes pro kazdou instalaci vlastni databazi a vlastni vhost
<VirtualHost *:443>
ServerName redmine1.cz
DocumentRoot /var/www/redmine1/public
<Directory /var/www/redmine/public>
RailsEnv production
RailsBaseURI /redmine/public
PassengerResolveSymlinksInDocumentRoot on
Order allow,deny
Allow from all
AllowOverride all
</Directory>
SSLEngine On
SSLCACertificateFile /etc/ssl/certs/RapidSSL.crt
SSLCertificateFile /var/www/blabla.crt
SSLCertificateKeyFile /var/www/blabla.key
</VirtualHost>
pak nainstalujes do slozky /var/www/redmine2/ novou instanci, vytvoris novy vhost soubor s upravenyma cestama a to je cele