Remove intermediate docker-gen.

Dockerfile

@@ -1,3 +0,0 @@
-FROM jwilder/docker-gen:latest
-
-COPY ./nginx.tmpl /etc/docker-gen/templates/nginx.tmpl

docker-compose.yml

@@ -2,9 +2,8 @@ version: "2"
 
 services:
   nginx:
-    restart: always
     image: nginx
-    container_name: nginx_proxy
+    restart: always
     ports:
       - "80:80"
       - "443:443"
@@ -15,18 +14,17 @@ services:
       - /var/docker/proxy/vhost.d:/etc/nginx/vhost.d:ro
 
   dockergen:
+    image: jwilder/docker-gen:latest
     restart: always
     depends_on:
       - nginx
-    build: .
-    image: typename/docker-gen
     command: -notify-sighup nginx_proxy -watch /etc/docker-gen/templates/nginx.tmpl /etc/nginx/conf.d/default.conf
     volumes_from:
       - nginx
     volumes:
+      - ./nginx.tmpl:/etc/docker-gen/templates/nginx.tmpl:ro
       - /var/run/docker.sock:/tmp/docker.sock:ro
 
 networks:
   default:
-    external:
     name: nginxproxy