Update Dockerfile

Dockerfile

@@ -41,7 +41,7 @@ RUN useradd -m -s /bin/bash -N -u $NB_UID $NB_USER && \
     mkdir -p / && \
     chown $NB_USER / && \
     chpasswd $NB_USER:ar-noc
-RUN sudo usermod -aG docker ${NB_USER}
+RUN usermod -aG docker ${NB_USER}
 
 USER $NB_USER