Display 4 cameras

Change-Id: I1ba835a0c703c08df15c3c13e4f3ba824274602f
diff --git a/README.md b/README.md
index e799671..a5277e3 100644
--- a/README.md
+++ b/README.md
@@ -29,6 +29,10 @@
 ```
 make docker-run
 ```
+```
+docker pull registry.aetherproject.org/aether-apps/person-detection-app:<tag>
+docker run -itu root:root --privileged --network host registry.aetherproject.org/aether-apps/person-detection-app:<tag>
+```
 
 ## Quick test
 ```
diff --git a/person_detection/app.py b/person_detection/app.py
index c188163..1cd5bb5 100644
--- a/person_detection/app.py
+++ b/person_detection/app.py
@@ -20,7 +20,7 @@
 @app.route('/')
 def index():
     """Video streaming home page."""
-    return render_template('index.html', devices=[0, 1])
+    return render_template('index.html', devices=[0, 1, 2, 3])
 
 
 def gen(camera):