Add Docker stuff

docker-compose.yml

@@ -0,0 +1,58 @@
+## Portainer stack for dndextended.
+## Env vars come from Portainer stack env or a .env file in the same dir.
+##
+## Required env:
+##   MONGODB_URI      - mongodb://mongo:27017/dndextended (or external cluster)
+##   AUTH_SECRET      - openssl rand -base64 32
+##   AUTH_URL         - public URL (https://dnd.example.com)
+##   AUTH_TRUST_HOST  - true (behind Traefik/nginx/Pinggy)
+##
+## Optional:
+##   MONGO_ROOT_USER, MONGO_ROOT_PASSWORD - if you want mongo auth (recommended in prod)
+
+services:
+  app:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    image: dndextended:latest
+    container_name: dndextended-app
+    restart: unless-stopped
+    ports:
+      - "${APP_PORT:-3000}:3000"
+    environment:
+      NODE_ENV: production
+      MONGODB_URI: ${MONGODB_URI:-mongodb://mongo:27017/dndextended}
+      AUTH_SECRET: ${AUTH_SECRET}
+      AUTH_URL: ${AUTH_URL}
+      AUTH_TRUST_HOST: ${AUTH_TRUST_HOST:-true}
+    depends_on:
+      mongo:
+        condition: service_healthy
+    networks:
+      - dnd
+
+  mongo:
+    image: mongo:7
+    container_name: dndextended-mongo
+    restart: unless-stopped
+    volumes:
+      - mongo_data:/data/db
+    environment:
+      MONGO_INITDB_ROOT_USERNAME: ${MONGO_ROOT_USER:-}
+      MONGO_INITDB_ROOT_PASSWORD: ${MONGO_ROOT_PASSWORD:-}
+    healthcheck:
+      test: ["CMD", "mongosh", "--quiet", "--eval", "db.adminCommand('ping').ok"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+      start_period: 20s
+    networks:
+      - dnd
+
+volumes:
+  mongo_data:
+
+networks:
+  dnd:
+    driver: bridge