IR sensors beer pong cups

I need some help. I wanted to build the beer pong table that has leds. I need some help in building the rgb pods so that when a cup is on the pod, it changes to the color green and when the cup is out, it turns red. How should I build this? Would reflective IR sensors do the job? how should I wire it up?

Do you have any experience in electronics or programming?

Do you know how to switch on LEDs? Or, detect anything?