Firefox 58 just added support for PWAs for Android:
See them in action here:
Here some more (developer) information about how they work:
This already works with a lot of websites like Twitter or Facebook. Now, why not make Discourse compatible, too? That would close the gap of a missing (real/native*) Android app.
But it feels like a native app, and just works with the web version, without much changes.
* As Discourse’ Android app is also just a webkit wrapper.