mount volume for log files

[mimusica]

I have a suggestion to mount a volume to the location where you keep your log files.
This might come in handy for security reasons, etc... At the moment, you don't have any volumes mounted, which means that your log files aren't persistent through container restarts. Therefor you don't know what caused the previous container to stop or restart.

create a docker volume and mount it to /var/log/asterisk (or wherever the log files are located)

[mimusica]

To be added to the dockerfile:

VOLUME ['/var/lib/asterisk','/var/log/asterisk','/var/spool/asterisk']