Reuse POSTGRES_PORT from environment variables

docker/docker-compose.build.yml

@@ -5,7 +5,7 @@ services:
     env_file:
       - ../.env
     environment:
-      DATABASE_URL: postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB}?connect_timeout=300&sslmode=prefer
+      DATABASE_URL: postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@postgres:${POSTGRES_PORT}/${POSTGRES_DB}?connect_timeout=300&sslmode=prefer
       NODE_ENV: production
       REDIS_HOST: redis
       REDIS_PASSWORD: ${REDIS_PASSWORD}

docker/docker-compose.yml

@@ -5,7 +5,7 @@ services:
     env_file:
       - ../.env
     environment:
-      DATABASE_URL: postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB}?connect_timeout=300&sslmode=prefer
+      DATABASE_URL: postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@postgres:${POSTGRES_PORT}/${POSTGRES_DB}?connect_timeout=300&sslmode=prefer
       NODE_ENV: production
       REDIS_HOST: redis
       REDIS_PASSWORD: ${REDIS_PASSWORD}