Add hub development dependency

Provide an easy way to work with the remote github repositories.
Configure Delayed Job to use a heroku compatible logger

Without this patch messages from Delayed Job are not visible in the
`heroku logs` command.  This patch addresses the problem by configuring
Delayed Job to use STDERR as a logger.
Add heroku compatible logging to the workers

Without this patch the worker processes are logging to a file that never
gets created.  This prevents delayed job workers from logging anywhere.
This patch addresses the problem by logging to STDERR in production
which is compatible and captured by Heroku.