Issue while building image.

[kumail-raza]

[invitro]

@kumail-raza you have to clone janus-gateway repo first

>> mkdir docker-janus && cd docker-janus
>> git clone https://github.com/meetecho/janus-gateway.git
>> cp ./Dockerfile janus-gateway/Dockerfile && cp ./docker-compose.yaml janus-gateway/docker-compose.yaml
>> cd janus-gateway
>> docker build -t my-domain/janus .
>> docker run -d --name janus-gateway my-domain/janus

[uniuuu]

@invitro @kumail-raza It duplicates #15

[uniuuu]

Made pull request with fix #27