Add geo-rep changes for Tiering volume  - update index.md
Add geo-rep changes for Tiering volume
 - update index.md

Signed-off-by: Saravanakumar Arumugam <2b13ecf0c1beba593c0ac5533ec3e39f55c0a4cb@redhat.com>

anoopcs9/glusterweb,SaravanaStorageNetwork/glusterweb,gluster/glusterweb,gluster/glusterweb,anoopcs9/glusterweb,kshlm/glusterweb,anoopcs9/glusterweb,gluster/glusterweb,anoopcs9/glusterweb,SaravanaStorageNetwork/glusterweb,SaravanaStorageNetwork/glusterweb,kshlm/glusterweb,SaravanaStorageNetwork/glusterweb,gluster/glusterweb,kshlm/glusterweb,kshlm/glusterweb