Add terraform example for creating cluster

[BretFisher]

Create a simple example of creating instances, installing docker, setting up security groups, LB's, etc. with Terraform, ideally for digital ocean and AWS.

Some examples: https://github.com/Praqma/terraform-aws-docker https://github.com/mlabouardy/terraform-aws-labs/tree/master/docker-swarm-cluster

[tmackness]

Happy to share mine I am working on.

Consists of:

• Digital Ocean
• Consul on Host
• Swarm auto join (managers & workers) on terraform apply
• In the process of tying in pulling stack files from private repo and deploying them