Upgrade to Docker 1.8 on ubuntu box

docker.sh

sudo su
echo deb https://apt.dockerproject.org/repo ubuntu-`cat /etc/lsb-release | grep DISTRIB_CODENAME | cut -d'=' -f2` main >> /etc/apt/sources.list.d/docker.list
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys F76221572C52609D
apt-get update
apt-get purge lxc-docker*
apt-get purge docker.io*
apt-get install docker-engine
exit

You should probably bail out of this script if /etc/lsb-release isn't found - it wasn't on my Debian box

-y at the purge commands, than copy&paste of the complete block would work

(At least in Linux Mint 17.2), you could also change this to lsb-release -cs instead of cat /etc/lsb-release | grep DISTRIB_CODENAME ...

Alternatively, apparently Docker provides a script to do this one in their docs:

wget -qO- https://get.docker.com/ | sh