Provide a semi-stable remote PBX system.

There is no preferred PBX but YaTE is pretty small and still
functional enough. Anyway Rhizomatica is using FreeSWITCH so
let's use that for testing.

This is creating a docker image with a SIP configuration that
will allow to record audio, have a DTMF menu using some fixed
numbers. Feel free to extend it to support bidirectional calls
and routing.

It is using the Debian packages and installs everything as I
am not interested to track dependencies and see what is missing.
Again feel free to optimize the size.


Build:
	make

	or

	docker build -t yourimagename:tag .


Run:

	docker run yourimagename:tag

SIP is exposed on 5060 of your port and audio on 6000-6020
