Add registation form

Hi, I need someone who can modify a open source invoice management script. Currently the script is only for 1 user. I want it so users can sign up and use the invoice manager in their business like a invoice service Here is the script: [login to view URL] User: admin AT [login to view URL] Pass: admin123 So their needs to be a sign up form where on the start page where users can register and then get a registration link to their email so they can sign in and start creating invoices, adding clients and all the other functionality.