Add howto for creating PTR records
Add howto for creating PTR records

PTR records can be a little tricky as they require a zone for both the
domain that the reverse lookup will point to as well as an
in-addr.arpa. zone.

Change-Id: I7f95dd0411f7715bbbfca11b1252cd77df1e88c6

tonyli71/designate,muraliselva10/designate,cneill/designate,kiall/designate-py3,cneill/designate,kiall/designate-py3,openstack/designate,kiall/designate-py3,muraliselva10/designate,ramsateesh/designate,ionrock/designate,muraliselva10/designate,cneill/designate,kiall/designate-py3,cneill/designate,cneill/designate-testing,ramsateesh/designate,tonyli71/designate,ionrock/designate,ionrock/designate,grahamhayes/designate,tonyli71/designate,grahamhayes/designate,cneill/designate-testing,openstack/designate,ramsateesh/designate,cneill/designate,cneill/designate-testing,kiall/designate-py3,openstack/designate,grahamhayes/designate