Building a CMS like Wordpress - Installation

Hello guys, so i want to build a CMS that can have multiple installations by users... So i need to design an installation similar to that of Wordpress requesting for Hostname, Database name etc from the user to set up the application.

Problem is, since CodeIgniter requires adding database autoload functions and predefined config, what is the best way to carry out this installation with CI. To dynamically pass and retain database variables obtained from the user..

Thank you for your help and responses.