My .vimrc-less VIM configuration.
~ $ git clone --recursive https://github.com/deuiore/.vim.git
~/.vim $ git pull --recurse-submodules
~/.vim $ git submodule update --recursive
To actually upgrade all submodule to their latest commits:
~/.vim $ git submodule foreach "(git checkout master; git pull)"
~/.vim $ git submodule add <URL> bundle/<NAME>
~/.vim $ git submodule deinit -f bundle/<NAME>
~/.vim $ git rm --cached bundle/<NAME>
~/.vim $ git config -f .gitmodules --remove-section submodule.bundle/<NAME>
~/.vim $ rm -rf bundle/<NAME> .git/modules/bundle/<NAME>