Add Pivotal Tracker start banner

Previously, there was no user notification that the story was being
started on Pivotal Tracker.  This change provides that information to
the user.
Merge branch 'start-notification'
Better description

Previously, the description for the Gem was the content of the
README.md file.  Unlike the Python world, this content is not
transformed when displayed on http://rubygems.org.  This change
simplifies the description to display better.
Merge branch 'description'