(fix) save parentPath
fix(World group type): remove the children field

According to the discussion with Santiago:
- Organizations are not children of World. Organisations have no parent

Chat log:
https://monimus.hipchat.com/history/room/269039/2013/11/30?q=Organizations+are+not+children#02:30:10
Merge pull request #68 from mykabam/improve-world-group-type

fix(World group type): remove the children field
Merge branch 'acl' of github.com:mykabam/kabam-kernel into acl
feat(groups): add UserGroup group type for rootGroup
feat(model-loader): support for adding mongoose plugins
Merge branch 'acl'
chore(package): bump to 0.3.8