Add defaults for some environment variables

+ Remove port bindings for the 'postgres' service

docker-compose.yml

@@ -14,17 +14,17 @@ services:
     image: postgres
     restart: always
     environment:
+      - POSTGRES_USER=server
       - POSTGRES_PASSWORD=${DATABASE_PASSWORD}
-    ports:
-      - 5432:5432
     container_name: "postgres"
   server:
     build: .
     restart: always
     container_name: "server"
     ports:
-      - ${PORT}:${PORT}
+      - ${PORT:-3000}:${PORT:-3000}
     environment:
-      - PORT=${PORT}
-      - DATABASE_URL=${DATABASE_URL}
+      - PORT=${PORT:-3000}
+      - DATABASE_URL=postgresql://server:${DATABASE_PASSWORD}@postgres:5432/management?schema=public
+      - DATABASE_USER=server
       - DATABASE_PASSWORD=${DATABASE_PASSWORD}