Yes, you’re not the only one. I asked a similar question in another thread some time ago.
My attempt with a YAML file in the PythonTurtle project is still unsuccessful. My main problem is that I must base the installation on Ubuntu 18.04 LTS Bionic for some dependencies not available on Trusty or Xenial.
At first sight it seems all easy just as Docker. But unfortunately it isn’t all that simple. I wish there was a clear recipe for packaging an AppImage.