Security group missing

I was unable to access the cache from the bastion host. It seems that the elasticache definition is missing the security group. I added this to the template:
```
security_group_ids = [
"${aws_security_group.default.id}"
]
```
and everything works fine.

Inspect the Terraform template's ElastiCache definition and compare its network access settings with the reported security_group_ids snippet. Validate the configuration and confirm the bastion host can access the cache; done means the example includes the required security group and applies successfully.

Written by the indexing model from the issue text.