Basic example of hosting both a simple Leaflet webmap and geojson layers on GitHub.
First, we created a webmap using Leaflet, named it index.html, and saved it in this github repository.
Then, we created a geojson layer on GeoJson.io and saved it to the data directory in this repository.
Next, we added the geojson layer to the map. You'll need the whole js directory here in your repo.
Finally, we activated GitHub pages for this repo...
Front facing webpage available here: https://outpw.github.io/GH_GrabBag