Gregory's Server
I've put together a tutorial on how to register an AppImage as a desktop application in Linux, trying to cover as many cases as possible and be as concise as possible, based on my personal experience.
https://retiolus.net/posts/how-to-register-appimage-destop-application-linux/
@retiolus on Manjaro I also had to run ```sudo update-desktop-database``` logging out and back in did not work.