Add redis-server init.d dependency - fixes #598

Created by: abevoelker

The documentation's example init.d script apparently will fail on system startup if redis-server isn't started first (see #598 (closed)). I added a startup dependency for redis-server to fix this (also replaced unicorn meta info with gitlab while I was there).

However, the init.d script will have to be added to system boot using insserv instead of update-rc.d to take advantage of dependency resolution.