Add replicas section

2.0/docs/apps/services.md

@@ -8,10 +8,6 @@ When you create a new app, app services created with the default configuration o
 
 You can also change your stack configuration and then upgrade an app instance's stack with override settings, in this case configurations from stack services will be transferred to app services.
 
-### Replica
-
-App service replica (or **ASR**) is a number of replicas for a service.
-
 ## Configuration
 
 - Each app services can be enabled or disabled
@@ -55,6 +51,10 @@ Here you can configure resources for a service. You can specify CPU and memory r
 
 Please note that resources request affects the deployment of the app service. For example, if your kubernetes cluster does not have enough resources to deploy an app service's pod with a requested amount of CPU or memory, the pod will be in a pending state until the resources become available. If your cluster has horizontal autoscaling enabled, it will scale up number of nodes to meet the demand.
 
+### Replicas
+
+Serverless app services can be easily scaled with the number of replicas. Some stateful services support scalability with extra replicas. 
+
 ### Links
 
 Here you can change [links](../services/index.md#links) between app services. Usually they are set up in a stack but can also be overridden per app instance.