Sad because FOSS people are using proprietary OS / preferring Apple. And it just sounded funny that core team didn't package it, because they all use MacOS.
Atom packages debs in their GitHub repo which work in Debian 8. There's no repo you can add to your sources that I am aware of, but you can manually download the deb from https://github.com/atom/atom/releases/tag/v1.11.0, run dpkg --install filename.deb, and get coding.