Add optional name + docs (#25)

* Add optional name

* docs: add README.md with project documentation

README.md

@@ -0,0 +1,81 @@
+# TP CI/CD
+
+A Node.js application providing a simple greeting service with a REST API. It includes a server built with Express, greeting logic, and comprehensive test
+suites (unit, integration, and end-to-end).
+
+## Features
+
+- **Greeting Functionality**: Generates personalized greetings via `src/greeting.js`.
+- **REST API Server**: Built with Express in `src/server.js`, supporting GET and POST endpoints for greetings.
+- **Testing**: Full test coverage with Jest:
+  - Unit tests in `tests/unit/greeting.test.js`.
+  - Integration tests in `tests/integration/app.test.js`.
+  - End-to-end tests in `tests/e2e/e2e.test.js`.
+- **Linting**: Configured with ESLint (via `.eslintrc.js` and `.eslintignore`).
+- **Node.js Version Management**: Uses `.nvmrc` to specify Node.js v22.19.0.
+
+## Prerequisites
+
+- Node.js ≥22.19.0 (use `.nvmrc` with nvm: `nvm use`).
+- npm (included with Node.js).
+
+## Installation
+
+1. Fork the repository:
+2. Install dependencies:
+
+```
+npm install
+```
+
+## Usage
+
+Start the server:
+
+```
+npm start
+```
+
+The server runs on port 3000 (or `process.env.PORT`). Endpoints:
+
+- `GET /hello/:name?`: Returns a greeting (e.g., "Hello world!" or "Hello world! From [name]").
+- `POST /hello`: Expects `x-name` header for the name.
+
+## Testing
+
+Run tests with Jest:
+
+- All tests: `npm test`
+- Unit tests: `npm run test:unit` (if defined; otherwise, use `npm test -- tests/unit/`)
+- Integration tests: `npm run test:integration` (if defined; otherwise, use `npm test -- tests/integration/`)
+- E2E tests: `npm run test:e2e` (if defined; otherwise, use `npm test -- tests/e2e/`)
+
+## Linting
+
+Check code quality:
+
+```
+npm run lint
+```
+
+## Project Structure
+
+- `src/greeting.js`: Core greeting logic.
+- `src/server.js`: Express server setup.
+- `tests/`: Test suites (unit, integration, e2e).
+- `.eslintrc.js`: ESLint configuration.
+- `.eslintignore`: Files/directories excluded from linting.
+- `.nvmrc`: Node.js version specification.
+- `package.json`: Project metadata, dependencies, and scripts.
+
+## Dependencies
+
+- **Runtime**: Express (web server), Axios (HTTP client), Supertest (testing utility).
+- **Dev**: ESLint (linting), Jest (testing).
+
+## Contributing
+
+1. Fork the repo.
+2. Create a feature branch.
+3. Run tests and linting.
+4. Submit a pull request.