Nginx example (#7207)

* Add sample nginx config file

- Taken from 0.13.x branch

* Add alternative setup for nginx

* Add brief note in the docs

contrib/container/docker-compose.yml

@@ -120,3 +120,17 @@ services:
             - ${INVENTREE_EXT_VOLUME}:/var/log:z
             - ${INVENTREE_EXT_VOLUME}:/data:z
             - ${INVENTREE_EXT_VOLUME}:/config:z
+
+    # alternative: run nginx as reverse proxy
+    # inventree-proxy:
+    #     container_name: inventree-proxy
+    #     image: nginx:stable
+    #     restart: always
+    #     depends_on:
+    #         - inventree-server
+    #     ports:
+    #         - ${INVENTREE_WEB_PORT:-80}:80
+    #         - 443:443
+    #     volumes:
+    #         - ./nginx.conf:/etc/nginx/conf.d/default.conf:ro,z
+    #         - ${INVENTREE_EXT_VOLUME}:/var/www:z