GitGutter is an amazing idea, that gained a lot of traction through the Sublime Text plugin created by J.D. Isaacks. The plugin lets you see which lines have been changed since the last git commit, right in your editor, while you’re coding. This is brilliant and it will prevent you from unwanted changes and make you more aware of how you’re changing code on a project that you don’t maintain alone.
I can only recommend you read his post on it, because it shows how quickly great ideas can take off, even if you don’t use Sublime. Since I spend most of my writing time in vim, I’m very fond of the vim-gitgutter plugin. It’s been working great and I spend less time going through my changes before the commit, because I’m more aware of what I actually have changed.
GitGutter for other editors: