I'll work on this guy

After trying for an hour or two to get the postgres scripts to work with a docker container, I created a docker-compose.yaml with the URL defaults that makes spinning it up the DB super easy for those (like me) who don't know postgres ins and outs. Is this something worth including in the PR?

version: '3'

services:
  # container name is:
  pg-substrate-archive:
    image: 'postgres:latest'
    ports:
      - 5432:5432 # localhost_port:container_port ; don't change container_port
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: 123 # change me
      POSTGRES_DB: kusama # default db name

basically sets up a db instance with user/pass as postgres and 123, kusama as the database name, and binds container port 5432 to localhost:5432. Too easy.

docker tl;dr we can stick in the readme:
start it up : docker-compose up -d
shut it down: docker-compose down
delete it: docker container stop pg-substrate-archive && docker container rm pg-substrate-archive

Yeah that would be great! Would start the journey to closing #206 as well, but yeah definitely a worthy addition imo

Is this something worth including in the PR?

I think it would be best as a separate PR; it's orthogonal to justifications.

I'm fine with anything that makes the first-use experience better but I do not want to bless Docker as the "preferred way" of running substrate-archive. :)

Since justifications are nullable values, I think this is blocked until this is solved: launchbadge/sqlx#1294 (comment).