If, for whatever reason, we need to allowlist someone to the public database: this is how you do it.
To allow DB access from external sources you'll need to add the IP address in 4 places:
https://us-east-1.console.aws.amazon.com/vpcconsole/home?region=us-east-1#RouteTables:
* In each of the 3 private subnets, add the IP address that should have access mapped to the IGW (internet gateway)https://us-east-1.console.aws.amazon.com/ec2/home?region=us-east-1#SecurityGroup:groupId=sg-02a44e75d6ea67cb8
* In the RDS "default" security group add the IP address