diff --git a/Dockerfile b/Dockerfile
index 375030c..bece532 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,8 @@
 FROM openresty/openresty:1.27.1.2-0-bookworm-buildpack
 
+WORKDIR /opt/app
+
+RUN apt-get update && apt-get install -y python3-pygments
 RUN luarocks install sitegen
 
-CMD ["openresty", "-p", "/opt/", "-g", "daemon off;"]
+CMD ["sh", "-c", "openresty -p `pwd` -g 'daemon off;'"]
diff --git a/README.md b/README.md
index d23f4cb..27f5242 100644
--- a/README.md
+++ b/README.md
@@ -43,11 +43,11 @@
 
 ### build site
 
-    $ docker run --rm -w /opt -v $PWD:/opt sitegen-openresty sitegen
+    $ docker run --rm -w /opt/app -v $PWD:/opt/app sitegen-openresty sitegen
 
-### start server container
+### start server
 
-    $ docker run --rm -it --init -w /opt -v $PWD:/opt -p 8080:8080 sitegen-openresty
+    $ docker run --rm -it --init -v $PWD:/opt/app -p 8080:8080 sitegen-openresty
 
 ### visit `localhost:8080` in web browser