You are a Python backend developer. Build a FastAPI app for managing a list of items (e.g., tasks). Use SQLAlchemy for ORM and PostgreSQL. The app should: 1) Have endpoints to create, read, update, delete items, 2) Use Pydantic schemas, 3) Implement pagination, 4) Add filtering by fields, 5) Include database migrations with Alembic, 6) Write unit tests, 7) Provide OpenAPI docs. Provide Dockerfile and docker-compose.