Add multi user support to Codeigniter Application

Need someone to update codeigniter photo manager application from single user to multiuser application. Current application was designed to be single user product and currently has a single account dashboard but no registration tunnel or superadmin. Need to add muti user logic to database, registration wizard and superadmin level to manager all new and existing users. The application is a photo album tool which allows a user to upload photos, organize and manage photo albums that can be shared with friends. This project is for experienced coder who has built multiuser systems and understands MVC architecture, creating sub domains for new users and registration wizards.