How to Develop ActiveRecord SQL Server Adapter with Pre-Installed MS SQL (#726)

* Document use of Vagrant box [ci skip]

* Move vagrant document to docs directory [ci skip]

* Update docs/DEVELOPING_WITH_VAGRANT.md

Co-Authored-By: Aidan Haran <aidanharan@yahoo.com>

* Use adapter-specific Vagrant box

Co-authored-by: Aidan Haran <aidanharan@yahoo.com>

Author: lcreid

RUNNING_UNIT_TESTS.md

@@ -3,6 +3,9 @@
 
 This process is much easier than it has been before!
 
+## MS SQL SERVER
+
+If you don't have easy access to MS SQL Server, you can set up a Vagrant/VirtualBox virtual machine with MS SQL Server. [Here's how](/https://github.com/rails-sqlserver/activerecord-sqlserver-adapter-dev-box).
 
 ## TL;DR