Add /items endpoint to return a list of items

main.py

@@ -5,3 +5,7 @@ app = FastAPI()
 @app.get("/")
 def read_root():
     return {"message": "Hello, World!"}
+
+@app.get("/items")
+def get_items():
+    return {"items": ["item1", "item2", "item3"]}