DocSync
It is a tool that accepts Google Docs Links and checks any changes
Given sender e-mail and password (used to help access the Google Doc), recipient email and password (helps send the e-mail), and docs link, this product will allow you to receive updates based on changes done on the document. Source code is posted in the GitHub! Note that the program is only for Windows platforms. More platforms coming soon!
GitHub: https://github.com/joalen/DocSync/