rlcdo isso mesmo, neste seu caso, o arquivo docker-compose.yml ficaria assim:
version: '2'
services:
novosga:
image: novosga/novosga:latest
restart: always
ports:
- "80:80"
- "2020:2020"
environment:
APP_ENV: 'prod'
# database connection
DATABASE_URL: 'mysql://usuario:senha@hostname-ou-ip:3306/database?charset=utf8mb4&serverVersion=5.7'
# default admin user
NOVOSGA_ADMIN_USERNAME: 'admin'
NOVOSGA_ADMIN_PASSWORD: '123456'
NOVOSGA_ADMIN_FIRSTNAME: 'Administrator'
NOVOSGA_ADMIN_LASTNAME: 'Global'
# default unity
NOVOSGA_UNITY_NAME: 'My Unity'
NOVOSGA_UNITY_CODE: 'U01'
# default no-priority
NOVOSGA_NOPRIORITY_NAME: 'Normal'
NOVOSGA_NOPRIORITY_DESCRIPTION: 'Normal service'
# default priority
NOVOSGA_PRIORITY_NAME: 'Priority'
NOVOSGA_PRIORITY_DESCRIPTION: 'Priority service'
# default place
NOVOSGA_PLACE_NAME: 'Box'
# Set TimeZone and locale
TZ: 'America/Sao_Paulo'
LANGUAGE: 'pt_BR'