Does not seem to work offline anymore

[michallepicki]

I used to show people the idea of offline-first by showing them this website. I know the application cache is getting deprecated, and probably that's why you removed this feature, but I would love to be able to spread the good word this way again. I believe it should be possible to make it work with service workers on github pages.

[gr2m]

The problem is currently to setup https for offlinefirst.org. Once we have that, we can make it work offline again