diff --git a/Dockerfile b/Dockerfile
index d4557d6..e03d4d5 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,3 @@
-# FROM openresty/openresty:bookworm-buildpack
 FROM buildpack-deps:trixie
 
 ARG version=3.8.2.1
diff --git a/Makefile b/Makefile
index 74c9081..9bb360e 100644
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,9 @@ serve:
 	docker run --rm -it --init -v $(PWD):/opt/app -p 8080:80 $(image) \
 		sh -c "openresty -p /opt/app -g 'daemon off;' -c conf/dev.nginx.conf"
 
+shell:
+	docker run --rm -it --init -v $(PWD):/opt/app -p 8080:80 $(image) bash
+
 build:
 	$(if $(file), $(docker-run) sitegen build $(file), $(docker-run) sitegen)
 
diff --git a/README.md b/README.md
index e59508c..3f1f34d 100644
--- a/README.md
+++ b/README.md
@@ -66,6 +66,10 @@
 
 Visit `localhost:8080` in web browser
 
+### start a shell
+
+    $ make shell
+
 ### start watcher
 
     $ docker exec -it container_name sitegen watch