Update startup.sh

desktop/km3book/startup.sh

 #!/bin/bash
 
 NOTEBOOK_DIR=$HOME/notebooks
+USER_ID=$(id -u)
+THE_USER=$USER
 
 cat << EOF > Dockerfile
 FROM docker.km3net.de/km3book:1.0.0
@@ -14,4 +16,5 @@ EXPOSE 22
 EOF
 
 sudo docker build -t km3book:1.0.0 -f Dockerfile .
-sudo docker run -p 8000:8888 -p 2200:22 -u $(id -u) -v $NOTEBOOK_DIR:$NOTEBOOK_DIR -it km3book:1.0.0
+chown -R $THE_USER $NOTEBOOK_DIR
+sudo docker run -p 8000:8888 -p 2200:22 -u $USER_ID -v $NOTEBOOK_DIR:$NOTEBOOK_DIR -it km3book:1.0.0