docs: init scheduler in the docker compose example

Signed-off-by: Mike Nguyen <hey@mike.ee>

daprdocs/content/en/operations/hosting/self-hosted/self-hosted-with-docker.md

@@ -138,6 +138,18 @@ services:
     command: ["./placement", "--port", "50006"]
     ports:
       - "50006:50006"
+
+  scheduler:
+    image: "daprio/dapr"
+    command: ["./scheduler", "--port", "50007"]
+    ports:
+      - "50007:50007"
+    # WARNING - This is a tmpfs volume, your state will not be persisted across restarts
+    volumes:
+    - type: tmpfs
+      target: /data
+      tmpfs:
+        size: "10000"
   
   networks:
     hello-dapr: null
@@ -147,6 +159,8 @@ services:
 
 To further learn how to run Dapr with Docker Compose, see the [Docker-Compose Sample](https://github.com/dapr/samples/tree/master/hello-docker-compose).
 
+The above example also includes a scheduler definition that uses a non-persistent data store for testing and development purposes.
+
 ## Run on Kubernetes
 
 If your deployment target is Kubernetes please use Dapr's first-class integration. Refer to the