Add vim-gitgutter

.gitmodules

@@ -31,3 +31,6 @@
 [submodule "dotfiles/vim/bundle/vim-taskwarrior"]
 	path = dotfiles/vim/bundle/vim-taskwarrior
 	url = https://github.com/farseer90718/vim-taskwarrior
+[submodule "dotfiles/vim/bundle/vim-gitgutter"]
+	path = dotfiles/vim/bundle/vim-gitgutter
+	url = git://github.com/airblade/vim-gitgutter.git

dotfiles/vim/bundle/vim-gitgutter

@@ -0,0 +1 @@
+Subproject commit 1742a8f568df549f4daeda90174b54d0c371501f