Adapt Dockerfile.productiono to openSUSE Leap 15.6

- No need to manually install bundler anymore
- bundle to vendor/bundle
- build nokogiri against system libraries
- expose the port foreman is using
- serve static files

docker-compose.yml.production-example

@@ -1,24 +1,25 @@
 services:
-  production_database:
-    image: postgres:12-alpine
+  postgres:
+    image: postgres:16-alpine
     environment:
       PGDATA: /var/lib/postgresql/data/pgdata
+      POSTGRES_USER: osem
       POSTGRES_PASSWORD: mysecretpassword
     volumes:
       - osem_production_database:/var/lib/postgresql/data/pgdata
-  production_web:
+  osem:
     build:
       context: .
       dockerfile: Dockerfile.production
     depends_on:
-      - production_database
+      - postgres
     ports:
-      - 8080:3000
+      - 80:5000
     env_file: .env.production # see dotenv.example file
     environment:
-     OSEM_DB_HOST: production_database
-     RAILS_SERVE_STATIC_FILES: 'true'
-    command: foreman start -p 3000
+     OSEM_DB_HOST: postgres
+     OSEM_DB_USER: osem
+     OSEM_DB_PASSWORD: mysecretpassword
     volumes:
       - osem_production_web_data:/osem/public/system
       - osem_production_web_assets:/osem/public/assets