How do I make a standalone application out of a Docker container?
The simple answer is: you can't.
The long answer is: Docker is not intended to be used to make cross platform standalone applications (but JAVA is, for example). Docker instead focuses on having a light weight container that acts like a virtual machine but basically isn't. It's just a box inside a linux(!) system that behaves like a virtual machine to install services into that can be separated clearly from each other that way. A proper use case example for docker would be to install a web application with a specific version of say apache and php in it to have a definitive environment guaranteed.
I'll like to create a python flask application that can run on any platform. I've put it in a Docker container. But unless I've misunderstood something the host machine still need docker installed to launch the container. Which in turn required Vagrant and and Ubuntu VM (at least on Mac). Am I missing something? What is the correct way to use a container as a standalone application?