-Submodules
-~~~~~~~~~~
-Only submodules using a gitfile (which means they were cloned
-with a git version 1.7.8 or newer) will be removed from the work
-tree, as their repository lives inside the .git directory of the
-superproject. If a submodule (or one of those nested inside it)
-still uses a .git directory, `git rm` will fail - no matter if forced
-or not - to protect the submodule's history.
-
-A submodule is considered up-to-date when the HEAD is the same as
-recorded in the index, no tracked files are modified and no untracked
-files that aren't ignored are present in the submodules work tree.
-Ignored files are deemed expendable and won't stop a submodule's work
-tree from being removed.
-