Improve quick start documentation and add health endpoint

test_app.py

@@ -0,0 +1,28 @@
+from fastapi import FastAPI
+from pydantic import BaseModel
+
+app = FastAPI(
+    title="FastAPI",
+    description="""
+## 🚀 Quick Start
+
+```bash
+curl -X GET http://127.0.0.1:8000/
+"""
+)
+
+class HealthResponse(BaseModel):
+     status: str
+
+@app.get("/")
+def root():
+     return "Hello World"
+
+@app.get(
+"/health",
+response_model=HealthResponse,
+summary="Health check endpoint",
+tags=["System"]
+)
+def health_check():
+    return HealthResponse(status="healthy")