Add resources for data replication

* Update 106-data-replication.md

I added a short description and video link that explains data replication within four minutes. Please take a look at it, thanks :)

* Update content/roadmaps/101-backend/content/108-more-about-databases/106-data-replication.md

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/101-backend/content/108-more-about-databases/106-data-replication.md

@@ -1 +1,7 @@
-# Data replication
+# Data Replication
+
+Data replication is the process by which data residing on a physical/virtual server(s) or cloud instance (primary instance) is continuously replicated or copied to a secondary server(s) or cloud instance (standby instance). Organizations replicate data to support high availability, backup, and/or disaster recovery.
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+
+<BadgeLink badgeText='Watch' href='https://youtu.be/fUrKt-AQYtE'>What is Data Replication?</BadgeLink>