Add rubygems package dependency.
Add rubygems package dependency.

The dashboard server requires the rubygems package in able to
use "gem" to install rack, rake and rdoc

Change-Id: I442d376eb5ab5aba3b1a17ad999b136885fb4958
Reviewed-on: https://review.openstack.org/23056
Reviewed-by: Monty Taylor <37c07a49ee3d5191376d758eb1d8298b34456b8e@inaugust.com>
Approved: Jeremy Stanley <98883b97e35b7bb1ac282bb863f2e9d917db0454@yuggoth.org>
Reviewed-by: Jeremy Stanley <98883b97e35b7bb1ac282bb863f2e9d917db0454@yuggoth.org>
Tested-by: Jenkins

trafodion/puppet-dashboard,trafodion/puppet-dashboard