$ boot2docker up
The command will return something that looks like the following statement. Copy and paste what boot2docker returned and execute it in your terminal:
$ export DOCKER_HOST=tcp://192.168.59.103:2375
You should see Docker running a supervisord session with Nginx and UWSGI. Now all that's left to do is open up your browser and type the IP address that boot2docker returned. In this example it was 192.168.59.103.
You should see the text Flask is running! in your browser. That's all there is to it!