* Allow additional security groups to be included for all workers and each worker group #47
* update changelog with reference to issue and be more descriptive
* Update CHANGELOG.md
* address pr comments and rebase
* rebase
* fix bug introduced by PR#115 that sets the AMI id to the default value of "" always
* rebase
* align default value of additional_security_group_ids to be pulled from local var workers_group_defaults_defaults