Added Docker build file

[0xStuart]

For those of us that want to avoid dependency problems, and use docker, here is a simple build file.

docker build -t stablestudio .
docker run -it --rm -p 3000:3000 --name stablestudio stablestudio

Suggest this gets added to the build process, and stored in GitHubs Docker repo. Then no need for users to build it.

[SeriousM]

You could add EXPOSE 3000 so that docker-tools can map it in their UI. I don't use them but plenty of users do.