Update Dockerfile

Dockerfile

@@ -7,9 +7,9 @@ RUN set -eux; apt-get update; \
     apt-get install -y --no-install-recommends xfce4 xfce4-terminal sudo; \
     #
     # add user to sudoers
-    usermod -aG sudo neko; \
+    usermod -aG neko; \
     echo "neko:neko" | chpasswd; \
-    echo "%sudo ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers; \
+    echo "%ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers; \
     # clean up
     apt-get clean -y; \
     rm -rf /var/lib/apt/lists/* /var/cache/apt/*