vim-gitgutter
A Vim plugin which shows git diff markers in the sign column
Vim-GitGutter is a plugin for Vim that surfaces version-control (Git) changes directly within your editing buffer by marking the sign column (the “gutter”) with indicators for added, removed or modified lines. As you edit files in a Git-tracked repository, Vim-GitGutter keeps the signs up-to-date (sometimes asynchronously) so you can immediately see which lines differ from the last committed state.