Has anyone come across a good and easy to install employee management script.
I’ve been looking around the web but can not find a solution that is not convoluted with Management terms and other Jargon.
Here is the situation and the functions I am looking for! 
I have a client that owns a restaurant delivery service. He has many independent contractors (Food Delivery Drivers) that he has to schedule, based on their availability. I need a script that allows his employees to log in, once a week, and schedule themselves for the shift times they can work.
My client will need the ability to set up a weekly pre-defined shift schedule each week, then his (delivery boys) need to be able to log in using an L/P and pick which shifts they can work, this will NEED to be on a first come, first serve basis. The schedule will open on 1 day, for example purposes, Thursday, and close on Sunday night at midnight for the following work week.
Your Help is greatly appreciated!