ASCII art is fun but not savvy for project managers and directors. This
patch slightly enhance the 'gating' documentation with colored diagrams.
This is made possible via http://blockdiag.com/ by Takeshi KOMIYA who
even took the time to write a sphinx extension. The version dependency
is at the very least 0.5.5, but might be higher :/
The zuul terminology for queues was changed to pipelines to help clean
up the code and make it easier to read and debug. Update the
documentation to reflect this terminology change.
Approved: James E. Blair <email@example.com>
Reviewed-by: James E. Blair <firstname.lastname@example.org>