Add Blue Green deployments

[davidobrien1985]

In order for this scenario to reflect a real example a blue - green deployment should be made possible.

This can be done by either using Load Balancers or just DNS names. First deployment creates the full stack. Following deployments would deploy the changed web server(s) in parallel, run TVT (Technical Verification Tests) and if they pass a release step in the deployment would cut the Load Balancer or DNS name over to the new web server(s).

This will lead to a real life example of deploying a web stack.