Docs: https://docs.docker.com/installation/debian/
apt-get purge lxc-docker*
apt-get purge docker.io*
apt-get install apt-transport-https
apt-key adv --keyserver hkp://pgp.mit.edu:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D
echo "deb https://apt.dockerproject.org/repo debian-jessie main" > /etc/apt/sources.list.d/docker.list
apt-get update
# verify that apt is pulling from the right repository:
apt-cache policy docker-engine
sudo apt-get install docker-engine
sudo service docker start
# verify docker is installed correctly:
sudo docker run --rm hello-world