improvement : shift to .db from MySql

Hello Everyone,

The **Hotel Management System** uses **MySql** to store its data. We need to need to remove all the dependencies from the MySql and use **sqlite** for the same purpose.

**_Note: Use .db file for the data work._**

**Changes needed in the following files:**

- main.py
- setup2.py

**_Thank You._**

Start by reading main.py and setup2.py to locate the current MySQL dependencies and data-access flow. Replace the MySQL storage path with SQLite using a .db file, then verify that the hotel management system can perform its existing data work without MySQL dependencies.

Written by the indexing model from the issue text.