Rewrite of the GitLab init-script providing the following features:
Conforms to the Debian, and inherently Ubuntu, init-script guidelines.
Is a valid POSIX or /bin/sh script as demanded by the guidelines.
Keeps track of the Unicorn and Sidekiq and their state separately.
Makes sure that both services start and stop appropriately before telling the user that they are or aren't running.
Handles cases where one service started and the other didn't. Highlighting it with a red warning text.
Knows the running state of both, not just the pids.
No longer uses the error prone "ps aux | grep $pid" method for finding out state.
Deals with stale pids caused by application crashes.
User set variables are properly escaped, ensures that paths with spaces in them work.
No more commands in variables as that sometimes leads to odd edge-cases.
The script now always runs as the $app_user, not as root or any other user.
No longer swallows errors produced.
This was my initial reason for rewriting the script: GitLab didn't start after an upgrade and there were nothing in the logs and no errors printed by the init script.
Has passed the peer review of #bash on irc.freenode.org
