Add section on automatic updates and use image by default [ci skip]

README.md

@@ -90,6 +90,19 @@ You can now run rimgo.
 sudo docker-compose up -d
 ```
 
+#### Automatic updates
+[Watchtower](https://containrrr.dev/watchtower/) can automatically update your Docker containers.
+
+Create a new `docker-compose.yml` file or add the watchtower section to your existing `docker-compose.yml` file.
+```yml
+version: "3"
+services:
+  watchtower:
+    image: containrrr/watchtower
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+```
+
 ### Build from source
 
 #### Requirements

docker-compose.yml

@@ -2,9 +2,9 @@ version: '3'
 
 services:
   rimgo:
-    #image: codeberg.org/video-prize-ranch/rimgo # Uncomment to use image, official image
+    image: codeberg.org/video-prize-ranch/rimgo # Official image
     #image: quay.io/pussthecatorg/rimgo # Unofficial image
-    build: .
+    #build: . # Uncomment to build from source
     ports:
       - 3000:3000
     restart: unless-stopped