CI to progressive web app

Hello All, 

Does anyone have any advice on converting to a PWA. I have tried to use this tutorial https://dev.to/pixeline/the-easy-way-to-...eb-app-77g but had no luck with upup as with its scope it (upup.sw file) will need to be in the controller dir or near the index.php file but, I have not been able to find out how to access it from those locations.