add user_hello dialog

app/handlers/user_handlers.py

@@ -0,0 +1,12 @@
+from aiogram import Router
+from aiogram.filters import CommandStart
+from aiogram.types import Message
+from aiogram_dialog import DialogManager
+
+from app.dialogs.user_dialog import StartSG
+
+router = Router(name="user_handlers")
+
+@router.message(CommandStart())
+async def command_start_process(message: Message, dialog_manager: DialogManager):
+    await dialog_manager.start(state=StartSG.start)