[bugfix] add __init__.py to database folder

Author: CuriousGu

src/infrastructure/database/__init__.py

@@ -0,0 +1,14 @@
+from .mongodb.connector import MongoDB
+from .mongodb.utils import get_service_details, get_user_details, block_user
+
+from .chromadb.connector import ChromaDB
+from .chromadb.utils import retriever_tool
+
+__all__ = [
+    "MongoDB",
+    "get_service_details",
+    "get_user_details",
+    "block_user",
+    "ChromaDB",
+    "retriever_tool"
+]