$ aws --profile ssnp --region us-east-1 ecr get-login
docker login -u AWS -p <PEM Text> -e none https://xxxx8739xxxx.dkr.ecr.us-east-1.amazonaws.com
Docker saves config in '/root/.docker/config.json'
Now Build a sample docker image
git clone https://github.com/awslabs/ecs-demo-php-simple-app
cd ecs-demo-php-simple-app
docker build -t docker-sandbox .
Tag it and push it to ECR
docker tag docker-sandbox:latest xxxx8739xxxx.dkr.ecr.us-east-1.amazonaws.com/docker-sandbox:latest
docker push xxxx8739xxxx.dkr.ecr.us-east-1.amazonaws.com/docker-sandbox:latest