Add proper readyness liveness probes to the unicorn chart
Now that the unicorn chart is running multiple processes, and ends with a tail -f, we need to add probes in order to cause the container to fail if one of the processes fails.
This is currently causing problems where unicorn fails because the database isn't ready, but workhorse does not. So the container never restarts when the database is ready.
This is one of the issues causing our master deploy not to work at the moment.