Bundles are managed with pathogen and are installed as submodules.
cd ~/.vim
git submodule add http://github.com/tpope/vim-fugitive.git bundle/fugitive
git add .
git commit -m "Installing fugitive as submodule."
cd ~
git clone http://github.com/peterjcaulfield/.vim.git
ln -s ~/.vim/.vimrc ~/.vimrc
cd ~/.vim
git submodule init
git submodule update
cd ~/.vim/bundle/fugitive
git pull origin master
git submodule foreach git pull origin master