simplified task definition

hello-world-task-def.json

{
    "family": "hello-world-task-def",
    "containerDefinitions": [
        {
            "name": "hello-world",
            "image": "<aws-account-id>.dkr.ecr.us-east-1.amazonaws.com/hello-world",
            "memoryReservation": 1024,
            "command": ["python", "/home/ubuntu/workspace/keras-docker-hello-world/hello_world.py"]
        }
    ]
}