Get working with docker cli args

docker-compose.yml

@@ -4,13 +4,14 @@ services:
   gerbil:
     image: gerbil
     container_name: gerbil
+    command: ["./gerbil", "--config", "/config/gerbil.conf"]
     cap_add:
       - NET_ADMIN
       - SYS_MODULE
-    volumes:
-      - ./config:/config
     ports:
       - 51820:51820/udp
+    volumes:
+      - ./config_example.json:/config/config.json
     sysctls:
       - net.ipv4.conf.all.src_valid_mark=1
-    restart: unless-stopped
+    restart: unless-stopped