Automate Rollback of Serverless application with AWS CodeDeploy

####Descrition: Using AWS CodeDeploy and AWS Lambda versions to deploy our functions in a blue-green deployment manner to reduce the occurrence of errors in our application in a production system.

#####Steps to Follow: Make sure you've install sam cli in your local, if not follow here.

1. Navigate to template.yaml file, read the comments in order to understand properly.
2. Run sam build command with,

sam build

3. Deploy the resources to aws cloud with the following cmd,

sam deploy --stack-name "serverless-codedeploy" --resolve-s3 --capabilities CAPABILITY_IAM

4. Navigate to functions/order.js and create some error intentionally and deploy again, in order to see rollback action.

5. Run to delete the deployed aws resources.

sam delete --stack-name "serverless-codedeploy"