Awesome article (as usual 🙂 ), Dave. Thanks for sharing the info. Two questions:

• In the network config section, you first show a commented-out line of:
  # config.vm.network "forwarded_port", guest: 80, host: 8080, host_ip: "127.0.0.1"
  and the next line shows the "configured" value being:
  host_ip: "127,0,0,1"
  Are the commas instead of periods in the IP address a typo?
• For getting VirtualBox images, do you have to get them from the Vagrant site, or will Vagrant work with images taken from sites such as OSBoxes: http://www.osboxes.org/ubuntu/ ??

P.S. I am also a huge fan / supporter of DbFit. I even wrote an article about it years ago, here on SQL Server Central (probably obsolete now):  Easy and Repeatable Testing of DB Code (Stored Procs, etc.) with DbFit