Update readme.md

Author: pacifiquem

rfid-transaction.ino/rfid-transaction/rfid-transaction.ino/readme.md

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 ## RFID Transaction Management System
 
-This project is an RFID Transaction Management System implemented using an Arduino and an RFID module. It allows users to perform transactions using either money or points. The system reads the card, authenticates, deducts the desired amount, and updates the card's data. The remaining money and points are displayed, and a buzzer sound indicates a successful transaction. The code is written in C++ and utilizes the MFRC522 library for RFID functionality. This system provides a simple and efficient solution for managing transactions using RFID technology.
+This project is an RFID Transaction Management System implemented using an Arduino and an RFID module. It allows users to perform transactions using either money or points. The system reads the card, authenticates, deducts the desired amount, and updates the card's data. The remaining money and points are displayed, and a buzzer sound indicates a successful transaction. The code is written in C++ and utilizes the MFRC522 library for RFID functionality. This system provides a simple and efficient solution for managing transactions using RFID technology.
+
+NB: `In this version we are using SD cards as our data store.`