Add RDS permanence clarification

[beyarkay]

Another little (and optional) change. I wasn't too sure if shuttle would keep the data stored in a DB across deployments/restarts or if I would need to find something to keep the data permanently. I couldn't find anything that was super explicit about this, but 🌸Rain🌸 (rainofthestorm) on discord helped me out.

Very happy to not include this one-liner if it's mentioned elsewhere in the docs or if those in the know think it's a bit over the top.

[joshua-mo-143]

Hmmmm, I think if this is a point of confusion then we should probably merge this. Originally the point of the aws-rds support crate was for Shuttle to allow provisioned databases on AWS RDS, but if this isn't clear then it'd be a good idea to clarify. @oddgrd @ivancernja thoughts?

[beyarkay]

Okay, here's some info to clarify where I was/wasn't confused:

• I understood that the aws-rds support was backed by AWS RDS
• I understood that shuttle hibernates idle services if they don't see traffic for a while (link)
• I wasn't sure how much about a service is preserved when shuttle hibernates a service.
• I wasn't sure if the RDS instance provisioned by shuttle was the same instance each time a service got restarted/got awoken from hibernation, or if a new instance was provisioned every time the service started/restarted.

[ivancernja]

@beyarkay Thanks for the clarification. Small change but it'll definitely help others!