create a class for sqflite (DbHelper)
packages :
- sqflite
https://pub.dev/packages/sqflite
- path
https://pub.dev/packages/path
read for more details
https://medium.com/@MarvelApps_/local-database-storage-in-flutter-using-sqflite-39651f3b2df0#:~:text=sqflite%20is%20a%20Flutter%20plugin,entries%20using%20SQL%2Dlike%20queries.
