demoapp listening address more wider, required to dockerized solution.

[chaggeus]

Demoapp listening address chanced to more wider: localhost => 0.0.0.0
In docker container call come over ip so localhost not work.
Added dockerized solution of demoapp that benefit is that it goes backround automaticly.

[aaltat]

Thank you for the PR.

This demo repo should be simple as possible and I agree that in most cases docker is good solution, in this repo it might leave people to wrong path. Therefore I am thinking that we should leave the docker out of this repository. But we can change the: HTTPServer.__init__(self, ('localhost', int(port)), to HTTPServer.__init__(self, ('0.0.0.0', int(port)), because that causes problems in docker usage.