Shameless plug: I developed GitEye which does exactly this. It's a chrome extension which adds a watch button for every file. When the "watched" file is changed

Shameless plug: I developed GitEye which does exactly this. It's a chrome extension which adds a watch button for every file. When the "watched" file is changed, the user receives an email. Check it here https://gitteye.herokuapp.com/ https://gitteye.herokuapp.com/