Renamed the FileIndexTest to IndexTest because it tests folders too

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Add permission to FolderIndex

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Add user permissions to FolderIndex and add tests

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>