I have taken my Montclair bus tracking web site and created an App for both Android and iOS that you can download for free in their app stores.
Developer: Marcus Dillavou
This came about because I have been unhappy about how iOS handles progressive web apps. Every time the app is brought to the foreground, iOS does a full reload, which can be slow and annoying. The native app handles this much nicer, and doesn’t ever have to reload the state.
To build the native apps, I used this handy tool: Progress Web App Builder. It takes your website, wraps it using Cordova, and generates both an iOS and an Android project. With only a few tweaks, I was able to get them submitted to the app store.