Update Dockerfile

Dockerfile

@@ -6,5 +6,6 @@ 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
-RUN echo gotty -w --port 7860 /bin/bash > /home/ubuntu/vm.sh
-CMD "bash", "vm.sh"
+RUN echo ./gotty -w --port 7860 /bin/bash > /home/ubuntu/vm.sh
+RUN chmod +x /home/ubuntu/vm.sh
+CMD "./vm.sh"