Update tutorial-custom-docker-image.md

Author: msangapu-msft

articles/app-service/containers/tutorial-custom-docker-image.md

@@ -45,7 +45,7 @@ cd docker-django-webapp-linux
 
 ## Build the image from the Docker file
 
-In the Git repository, take a look at _Dockerfile_. This file describes the Python environment that is required to run your application. Additionally, the image sets up an [SSH](https://www.ssh.com/ssh/protocol/) server for secure communication between the container and the host. The script `init.sh` starts the SSH service and Python server.
+In the Git repository, take a look at _Dockerfile_. This file describes the Python environment that is required to run your application. Additionally, the image sets up an [SSH](https://www.ssh.com/ssh/protocol/) server for secure communication between the container and the host. The last line in the _Dockerfile_, `ENTRYPOINT ["init.sh"]`, invokes `init.sh` to start the SSH service and Python server.
 
 ```Dockerfile
 FROM python:3.4