Based off https://www.circuits.dk/install-grafana-influxdb-raspberry/ & http://docs.grafana.org/installation/debian/
sudo apt-get install apt-transport-https curl && curl https://bintray.com/user/downloadSubjectPublicKey?username=bintray | sudo apt-key add -
echo "deb https://dl.bintray.com/fg2it/deb-rpi-1b jessie main" | sudo tee -a /etc/apt/sources.list.d/grafana.list
echo "deb https://dl.bintray.com/fg2it/deb jessie main" | sudo tee -a /etc/apt/sources.list.d/grafana.list