Taken from https://www.digitalocean.com/community/tutorials/how-to-install-and-use-docker-on-ubuntu-16-04
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
sudo apt-get install \
apt-transport-https \
ca-certificates \
curl \
software-properties-common
sudo apt-get update
apt-cache policy docker-ce
sudo apt-get install -y docker-ce
sudo systemctl status docker
sudo usermod -aG docker ${USER}
su - ${USER}
id -nG