Update Dockerfile

Dockerfile

@@ -6,4 +6,5 @@ RUN chown ubuntu:ubuntu /home/ubuntu
 RUN tar -xf gotty_linux_386.tar.gz
 RUN mv gotty /home/ubuntu/gotty
 RUN chmod +777 /home/ubuntu/gotty
-CMD ["~/gotty", "--port 7860" "-w", "/bin/bash"]
+RUN echo gotty -w --port 7860 /bin/bash > /home/ubuntu/vm.sh
+CMD "bash", "vm.sh"