diff --git a/Dockerfile b/Dockerfile
index 9c93cd8..008bcbf 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,8 +2,9 @@ FROM openresty/openresty:1.27.1.2-0-bookworm-buildpack
 
 WORKDIR /opt/app
 
-RUN apt-get update && apt-get install -y python3-pygments pandoc
+RUN apt-get update && apt-get install -y python3-pygments pandoc lua-inotify
 RUN luarocks install sitegen
+RUN luarocks install inotify INOTIFY_INCDIR=/usr/include/x86_64-linux-gnu/
 
 CMD ["sh", "-c", "openresty -p `pwd` -g 'daemon off;'"]
 # CMD ["openresty", "-p", "/opt/app", "-g", "daemon off;"]
diff --git a/README.md b/README.md
index 442d9e8..1d5aa82 100644
--- a/README.md
+++ b/README.md
@@ -58,6 +58,10 @@
 
 ### visit `localhost:8080` in web browser
 
+### start watcher
+
+    $ docker exec -it container_name sitegen watch
+
 ## todo
 
 * titleize slugs