Vagrant ssh to Docker container
You run a docker container not a VM as your provider, so the vagrant workflow is broken as you cannot ssh into docker container.
When you're using the docker provider you can run your command using vagrant docker-run; see the doc
If you were running docker directly, you will not be able to ssh directly, there's some hacks to workaround this but vagrant as an abstraction of the provider cannot make it as a simple ssh command and its not official support.