Add Express + MongoDB Notes API Docker Compose example

[Kshashi22]

Description

This pull request adds a new Docker Compose example demonstrating how to build and run an Express.js REST API backed by MongoDB.

Features

• Express.js REST API
• MongoDB database
• Mongoose ODM
• Docker Compose configuration
• Dockerfile for the backend service
• CRUD operations for notes
• Example README with deployment instructions

API Endpoints

• GET /
• GET /notes
• POST /notes
• GET /notes/:id
• PUT /notes/:id
• DELETE /notes/:id

Testing

Run:

docker compose up -d