The kernel pull-request tracker bot

Since the beginning, one part of the kernel-development task has been
watching the mainline to see whether one's work had been merged. That is
about to change with the advent of the pull-request tracker
bot, which will inform maintainers when one of their pull requests has
made it into the mainline. Konstantin Ryabitsev, who put this service
together, plans to expand it to other trees once things have settled down.