Its a shame that a Linux version is not included. A significant volume of developers work on Linux. If doing a multi platform application, why exclude it?
I'm actually working on a Github Desktop "clone" using Electron (so that it'll be "cross-platform"). I'm also working a Gtk+3 version (since I have more experience with that), but I haven't gotten too far.
Ping me if you want to see it. Planning to open source it soon.