Security groups should support instances

#1

Simple use case:

I’m using haproxy on a gateway to forward traffic to a web server using the private network

Problem
I want to firewall the web server to allow connections only from the gateway (because as we know the private network is accessible by all scaleway customers) but the gateway private IP is not static forcing me to allow connections from all scaleway customers

A security group only allows IPs, not dns public/private dns name, not instance or instance ID.

Sollution:

Please add to security groups the option of using an instance as source instead of IPs