Add expense tracker project

[DIGVIJAYGOWDA]

Description

Added a beginner-friendly command-line Expense Tracker built with Python.

Features

• Add expenses
• View all expenses
• Calculate total expenses
• Delete expenses
• Store expenses using JSON
• Load previously saved expenses

Files Added

• expense_tracker.py - Main application
• expenses.json - Local expense storage
• README.md - Project documentation

Testing

The application was tested for:

• Adding expenses
• Viewing expenses
• Calculating total expenses
• Deleting expenses
• Invalid input handling
• Persistence after restarting the application