Docker volume backup and restore postgres:10 image & named volume - postgresql

Question

I'm trying to backup/restore a docker volume. This volume is a named volume attached to a postgres:10 db image. The volume is seeded via a pg_dump/restore. I'm using docker-compose and here is what it looks like:
services:
db:
image: postgres:10
ports:
- '5432:5432'
volumes:
- postgres-data:/var/lib/postgresql/data
volumes:
postgres-data:
driver: local
localstack-data:
driver: local
Here is what the mounted volume looks like on the db service:
"Mounts": [
{
"Type": "volume",
"Name": "postgres-data",
"Source": "/var/lib/docker/volumes/postgres-data/_data",
"Destination": "/var/lib/postgresql/data",
"Driver": "local",
"Mode": "rw",
"RW": true,
"Propagation": ""
}
]
Now, when I say "backup/restore", I mean I want to be able to have a backup of the data inside that volume so that after I have messed all the data up, I can simply just replace it with the backup and have fresh data. A simple "restore w/ snapshot" type of action. I'm following the documentation found on docker.
To test it:
I add a user to my postgres-data
Stop my container docker stop $(docker ps -q)
Perform backup (db_1 is container name): docker run --rm --volumes-from db_1 -v $(pwd):/backup busybox tar cvf /backup/backup.tar /var/lib/postgresql/data
Delete user after backup is complete
Here is an example of the output of backup command that follows w/ NO errors:
tar: removing leading '/' from member names
var/lib/postgresql/data/
var/lib/postgresql/data/PG_VERSION
var/lib/postgresql/data/pg_hba.conf
var/lib/postgresql/data/lib/
var/lib/postgresql/data/lib/postgresql/
var/lib/postgresql/data/lib/postgresql/data/
var/lib/postgresql/data/lib/postgresql/data/PG_VERSION
var/lib/postgresql/data/lib/postgresql/data/pg_hba.conf
var/lib/postgresql/data/lib/postgresql/data/lib/
var/lib/postgresql/data/lib/postgresql/data/lib/postgresql/
var/lib/postgresql/data/lib/postgresql/data/lib/postgresql/data/
var/lib/postgresql/data/lib/postgresql/data/lib/postgresql/data/PG_VERSION
var/lib/postgresql/data/lib/postgresql/data/lib/postgresql/data/pg_hba.conf
var/lib/postgresql/data/lib/postgresql/data/lib/postgresql/data/pg_stat/
Once done, tar file gets created. Now, maybe the error is with the path? If you look at the output I'm seeing lib/postgresql/data nested over and over. Not sure if that is an okay result or not.
Once done, I perform the "restore": docker run --rm --volumes-from db_1 -v $(pwd):/backup busybox sh -c "cd /var/lib/postgresql/data && tar xvf /backup/backup.tar --strip 1"
What I expect: To see the deleted user back in the db. Basically, to see the same data that was in the volume when I performed the backup.
What I'm seeing: the data is not getting restored. Still same data. No user restored and any data that has been changed stays changed.
Again, perhaps what I'm doing is the wrong thing or "overkill" for a simple desire to hot swap out used volumes with a fresh, untouched one. Any ideas would be helpful from debugging or a better approach.