add: postgresdb alternative

.env.sample

@@ -2,6 +2,9 @@ TYPE=gitea
 
 DOMAIN=gitea.example.com
 LETS_ENCRYPT_ENV=production
+COMPOSE_FILE="compose.yml"
+COMPOSE_FILE="$COMPOSE_FILE:compose.mariadb.yml"
+# COMPOSE_FILE="$COMPOSE_FILE:compose.postgres.yml"
 
 GITEA_DOMAIN=git.example.com
 GITEA_ALLOW_ONLY_EXTERNAL_REGISTRATION=true
@@ -27,7 +30,7 @@ SECRET_JWT_SECRET_VERSION=v1 # length=43
 SECRET_SECRET_KEY_VERSION=v1 # length=64
 
 # SMTP Mailer
-# COMPOSE_FILE="compose.yml:compose.smtp.yml"
+# COMPOSE_FILE="$COMPOSE_FILE:compose.smtp.yml"
 # GITEA_SMTP_MAILER_ENABLED=1
 # GITEA_MAILER_HOST=mail.gandi.net:465
 # SECRET_SMTP_PASSWORD_VERSION=v1