diff --git a/Dockerfile b/Dockerfile
index 06ec54a..e644cb9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,12 +3,12 @@ ARG NB_USER="jovyan"
 ARG NB_UID="1000"
 ARG NB_GID="100"
 FROM ${LAB_IMAGE}
-
-#USER root
+SHELL ["/bin/bash", "-o", "pipefail", "-c"]
+USER root
 RUN apt-get update --yes && \
     apt-get install --yes --no-install-recommends \
     git-lfs 
-#USER ${NB_UID}
+USER ${NB_UID}
 RUN echo "install custom extensions"
 RUN pip install --extra-index-url https://git.sandbox.iuk.hdm-stuttgart.de/api/packages/grosse/pypi/simple jupyterlab-sandbox-theme==0.1.4
 RUN pip install --extra-index-url https://git.sandbox.iuk.hdm-stuttgart.de/api/packages/grosse/pypi/simple jupyterlab-sandbox-announcement==0.1.3