Docker-compose:

version: '3' services:

app:
  image: 'jc21/nginx-proxy-manager:latest'
  ports:
    - '22280:80'
    - '22281:81'
    - '22443:443'
  environment:
    DB_MYSQL_HOST: "db"
    DB_MYSQL_PORT: 3306
    DB_MYSQL_USER: "[some username]"
    DB_MYSQL_PASSWORD: "[some strong password]"

    DB_MYSQL_NAME: "npmdb"
  volumes:
    - ~/docker/containers/nginx-proxy-manager/data:/data
    - ~/docker/containers/nginx-proxy-manager/letsencrypt:/etc/letsencrypt
db:
  image: 'jc21/mariadb-aria:latest'
  environment:
    MYSQL_DATABASE: 'npm'
    DB_MYSQL_USER: "[some username]"
    DB_MYSQL_PASSWORD: "[some strong password]"

    MYSQL_ROOT_PASSWORD: '[some other strong password]'

  volumes:
    - ~/docker/containers/nginx-proxy-manager/data/mysql:/var/lib/mysql