Update gem description

This tool is less "opinionated" now that it supports configuration.

Change-Id: I887939bd3a4401c297e2d213d9e8445a04086eb3
Reviewed-on: http://gerrit.causes.com/44723
Tested-by: jenkins <jenkins@brigade.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>