added functions to money.py

[churyan7]

Short description of what this resolves:

add functions to money module

Changes proposed in this pull request:

• added ability to deposit money into account, to complement expenditures
• added ability to reset the money account

Status (please check what you already did):

• [ x ] made PR ready for code review
• [ x ] added some tests for the functionality
• [ x ] updated the README with example

Fixes: #