add optional redirection

compose.yml

@@ -23,7 +23,10 @@ services:
         - "backupbot.backup=true"
         - "backupbot.backup.path=/usr/share/nginx/html"
     environment:
-      DEFAULT_CONF_FILE: /etc/nginx/conf.d/default.conf
+      - DEFAULT_CONF_FILE=/etc/nginx/conf.d/default.conf
+      - REDIRECT_FROM_PATH
+      - REDIRECT_TO_URL
+      - REDIRECT_TYPE
     volumes:
       - content:/usr/share/nginx/html
     configs:
@@ -42,7 +45,8 @@ volumes:
 configs:
   nginx_default_conf:
     name: ${STACK_NAME}_nginx_default_conf_${NGINX_DEFAULT_CONF_VERSION}
-    file: default.conf
+    file: default.conf.tmpl
+    template_driver: golang
 
 networks:
   proxy: