Remove outdated docker-machine stuff

Makefile

@@ -1,26 +0,0 @@
-# Prepares the virtual box instance
-prepare:
-	# Creates the virtual box
-	-docker-machine create -d virtualbox --virtualbox-boot2docker-url https://github.com/boot2docker/boot2docker/releases/download/v1.13.0-rc1/boot2docker.iso pwd && true
-	# Makes sure the docker daemon has the DinD image pulled
-	-docker-machine ssh pwd "docker pull franela/pwd-1.12.3-experimental-dind"
-	# Daemon should be swarm
-	-docker-machine ssh pwd "docker swarm init --advertise-addr $$(docker-machine ip pwd)"
-	# Stops to daemon to do further configurations on the box
-	-docker-machine stop pwd
-	# Adds the host GOPATH as a shared folder in the box
-	-VBoxManage sharedfolder add pwd --name gopathsrc --hostpath ${GOPATH}src --automount
-	# Do port forwaring so we can reach the app using localhost:3000
-	-VBoxManage modifyvm pwd --natpf1 "localhost,tcp,,3000,,3000"
-
-# Starts the virtual box instance
-start:
-	# Starts the machine
-	-docker-machine start pwd
-	# Make sure the folder where we'll mount the shared folder exists
-	docker-machine ssh pwd "sudo mkdir -p /go/src"
-	# Mount the host's GOPATH shared folder
-	docker-machine ssh pwd "sudo mount -t vboxsf gopathsrc /go/src"
-
-
-.PHONY: prepare start run

README.md

@@ -9,11 +9,7 @@ A live version is available at: http://play-with-docker.com/
 
 ## Requirements
 
-Docker 1.13+ is required. If you're running an older version or you just want to run PWD in a VM you can use docker-machine with the following command:
-
-```
-docker-machine create -d virtualbox <name>
-```
+Docker 1.13+ is required. 
 
 The docker daemon needs to run in swarm mode because PWD uses overlay attachable networks. For that
 just run  `docker swarm init` in the destination daemon.
@@ -21,11 +17,6 @@ just run  `docker swarm init` in the destination daemon.
 It's also necessary to manually load the IPVS kernel module because as swarms are created in `dind`, 
 the daemon won't load it automatically. Run the following command for that purpose: `sudo modprobe xt_ipvs`
 
-If you are developing, there is a `Makefile` file with 2 targets that can set the whole environment for you (using docker-machine and virtual box).
-Just run once `make prepare`, which will create & prepare the docker-machine environment.
-Additionally, every time you want to start you environment run `make start`.
-And to start the application on a container on the docker machine host, run: `eval $(docker-machine env pwd) && docker-compose up`
-
 
 ## Development