Add Dockerfile for easy local testing

[rawbertp]

I created a Dockerfile which allows for easy local testing. This is for development purposes only and might be useful for other contributors too.

[andi34]

"apt install" should be enough instead "apt-get install"

[rawbertp]

"apt install" should be enough instead "apt-get install"

See here why apt-get should be used in scripts rather than apt: https://askubuntu.com/a/990838

[andi34]

"apt install" should be enough instead "apt-get install"

See here why apt-get should be used in scripts rather than apt: https://askubuntu.com/a/990838

Then Line 30 (&& apt update && apt install -y yarn) needs an update

[sualko]

Looks good, but I have to give it a try if I have more time.