[Solved] Docker not accepting environment variable

I'm trying to create a postgres container, I have the following in my Docker Compose:

db:
  container_name: db
  image: postgres
  restart: always
  environment:
    #POSTGRES_USER="postgres"
    POSTGRES_PASSWORD: HDFnWzVZ5bGI
  ports:
    - 5432:5432
  volumes:
    - pgdata:/var/lib/postgresql/data
adminer:
  container_name: adminer
  image: adminer
  restart: always
  ports:
    - 8338:8080

And yet Docker keeps saying that the database is initialized and that the superuser is not specified. Where am I going wrong?

I've tried with and without equals, a hyphen, quotation marks. No matter what I try, it won't see it.

#Solution:

Find:

  volumes:
    - pgdata:/var/lib/postgresql/data

Replace:

  volumes:
    - /opt/postgres/data:/var/lib/postgresql/data

More info: https://lazysoci.al/comment/8597610