add all services as examples

dash-apm-python/step_3.md

@@ -7,11 +7,50 @@ Our services should look like:
 
 ``` yaml
 frontend:
-    environment:
-      - DATADOG_SERVICE_NAME=frontend
-      - DATADOG_TRACE_AGENT_HOSTNAME=agent
-      - DD_TRACE_ANALYTICS_ENABLED=true
-```
+  env_file: ".env"
+  environment:
+    - FLASK_APP=api.py
+    - FLASK_DEBUG=1
+    - DATADOG_SERVICE_NAME=frontend
+    - DATADOG_TRACE_AGENT_HOSTNAME=agent
+    - DD_TRACE_ANALYTICS_ENABLED=true
+```{{copy}}
+
+``` yaml
+node:
+  env_file: ".env"
+  environment:
+    - DD_SERVICE_NAME=users-api
+    - DD_TRACE_AGENT_HOSTNAME=agent
+    - DD_TRACE_ANALYTICS_ENABLED=true
+`{{copy}}
+
+``` yaml
+pumps:
+  env_file: ".env"
+  environment:
+    - FLASK_APP=pumps.py
+    - FLASK_DEBUG=1
+    - POSTGRES_PASSWORD=postgres
+    - POSTGRES_USER=postgres
+    - DATADOG_SERVICE_NAME=pumps-service
+    - DATADOG_TRACE_AGENT_HOSTNAME=agent
+    - DD_TRACE_ANALYTICS_ENABLED=true
+`{{copy}}
+
+``` yaml
+sensors:
+  env_file: ".env"
+  environment:
+    - FLASK_APP=sensors.py
+    - FLASK_DEBUG=1
+    - POSTGRES_PASSWORD=postgres
+    - POSTGRES_USER=postgres
+    - DATADOG_SERVICE_NAME=sensors-api
+    - DATADOG_TRACE_AGENT_HOSTNAME=agent
+    - DD_TRACE_ANALYTICS_ENABLED=true
+`{{copy}}
+
 
 Afterwards restart docker services: