In order for the model to work, you need 2 more config files:
1. "yolov3.cfg"
2. "yolov3.weights"
these files are too big for github so you can download them in this link: https://pjreddie.com/darknet/yolo/
If you choose to download another config file from the one I used, please remember to update these changes in code under modelConfiguration and modelWeights variables.