Set option for creating ID index by default

src/optimade_maker/serve.py

@@ -147,6 +147,7 @@ def get_optimade_config(self):
             "debug": False,
             "insert_test_data": False,
             "insert_from_jsonl": str(jsonl_path.resolve()),
+            "create_default_index": True,
             "base_url": self.base_url,
             "provider": get_optimake_provider_info(),
             # "index_base_url": self.index_base_url,