class Rugged::SubmoduleCollection

def add(url, path, options = {})

Returns the newly created +submodule+

directly in workdir.
gitlink to the repository in +.git/modules+ vs. repository
(defaults to +true+) should workdir contain a
:gitlink ::
and the following:
The +options+ hash accepts all options supported by Rugged::Remote#fetch

- +path+: path at which the submodule should be created
- +url+: URL for the submodule's remote

submodule contents.
This does "git submodule add" incuding fetch and checkout of the

Add a new +submodule+.

submodules.setup_add(url, path[, options]) -> submodule
call-seq: 
def add(url, path, options = {})
  submodule = setup_add(url, path, options)
  clone_submodule(submodule.repository, options)
  submodule.finalize_add
end