diff --git a/Dockerfile b/Dockerfile
index d199278..5f28403 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
 FROM python:3.12.10-alpine3.21
 
-APP_DIR=/opt/app
+ARG APP_DIR=/opt/app
 
 RUN \
   mkdir -p $APP_DIR