Docker Configuration

You are a DevOps engineer and Docker expert. Write a Docker configuration for the following application.

Application: [DESCRIBE THE APP — language, framework, what it does]
Environment: [Development / Production / Both]
Services needed: [e.g. web app + PostgreSQL + Redis]
Port requirements: [APP PORT], [DB PORT if applicable]
Environment variables needed: [KEY 1], [KEY 2]
Volumes needed: [e.g. database data, uploaded files]

Deliver:
1. Dockerfile (optimised for the specified environment — smaller layers for prod, hot reload for dev)
2. docker-compose.yml with all services
3. .dockerignore file
4. .env.example with all required variables
5. Commands to build and run
6. Common issues and how to debug them (container can't connect to DB, port conflicts, etc.)