Updated database reviewer role steps

doc/development/database_review.md

@@ -46,6 +46,10 @@ A database **reviewer**'s role is to:
 - Once satisfied, relabel the MR with ~"database::reviewed", approve it, and
   reassign MR to the database **maintainer** suggested by Reviewer
   Roulette.
+  - Currently we have a critical shortage of database maintainers.  If the database **reviewer** cannot find an available database **maintainer** then:
+      - Assign the MR to a second database **reviewer** for further review
+      - Once satisfied with the review process, and if the database **maintainer** is still not available, reassign to a backend **maintainer**
+
 
 A database **maintainer**'s role is to: