docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?.See 'docker run --help'.

For anyone also having this issue. The solution for me was to:

• Run the Docker Quickstart Terminal app
• Run docker-machine restart default
• Run eval $(docker-machine env default)

Apparently you need to run the eval $(docker-machine env default) every time you run the quick start terminal.