Add a user registration system to my web app.

I have a self hosted project management web app. All the functionality for the software is complete. It is currently designed to be used with just 1 admin. So there is no user sign up process. What I need done is to build a user registration system where users are able to sign up to the system and be part of a company where they are able to create projects and invite other users to join that company. Currently the software is written in angular.js for the front end and PHP (MVC style) for the backend using a mysql database. I have created a repository on github for you to take a look at the software before you make any bids [login to view URL] You can also view the software running live here [login to view URL] What I basically need is to convert this web app to be SAAS or subscription based software. Task required - Build a user sign up process so that a user (company owner) can sign up and create projects - Create functionality so that all users are part of a company. Users are only allowed to view projects that belong to the company or projects they have been invited to. Skill required - Angular.js - PHP MVC - MYSQL