Add Dockerfile
Add Dockerfile

To start the examples/standalone_dns/, do:
docker build -t vaping ./
docker run --name vaping -p 7021:7021 vaping
docker rm -f vaping

Signed-off-by: Justin Cinkelj <3de87b13b805a37198b1c9d4e7ffe5d1a4cee8d3@xlab.si>

20c/vaping,20c/vaping