fix url with sync

Author: iamfortune

modules/ROOT/pages/introduction.adoc

@@ -100,10 +100,10 @@ Interact with Sync Gateway programmatically using comprehensive REST API interfa
 Synchronize data between Sync Gateway and your applications, servers, and other Sync Gateway instances.
 
 * xref:sync-with-server.adoc[]
-* xref:sync-with-application.adoc[]
-* xref:inter-sync-gateway-replication.adoc[]
+* xref:sync-using-app.adoc[]
+* xref:inter-syncgateway-overview.adoc[]
 * xref:delta-sync.adoc[]
-* xref:image-processing.adoc[]
+* xref:import-processing.adoc[]
 
 == Manage