another fix

Dockerfile

@@ -3,7 +3,8 @@ FROM jupyter/scipy-notebook
 LABEL Maintainer="Wolfgang Hottgenroth <wolfgang.hottgenroth@icloud.com>"
 LABEL ImageName="registry.gitlab.com/wolutator/registry.gitlab.com/wolutator/"
 
-ENV JUPYTER_GATEWAY_URL ""
+ARG GATEWAY_URL
+ENV E_GATEWAY_URL ${GATEWAY_URL}
 
 RUN \
   pip install influxdb && \
@@ -11,5 +12,5 @@ RUN \
   fix-permissions $CONDA_DIR && \
   fix-permissions /home/$NB_USER 
 
-CMD ["start-notebook.sh", "--NotebookApp.token=''"]
+CMD start-notebook.sh --NotebookApp.token='' --NotebookApp.base_url=$E_GATEWAY_URL