Add documentation to the usage with Active Directory (#2303)
Add documentation to the usage with Active Directory (#2303)

Co-authored-by: Brennan Kinney <901e3df23fbf3fa06dbd02d7dc18fa953b9694f7@users.noreply.github.com>
Co-authored-by: Georg Lauterbach <b8f844365803e0d6eec087a5a4ee33035992d170@users.noreply.github.com>
tomav/docker-mailserver,tomav/docker-mailserver,tomav/docker-mailserver