Use async.mapSeries() instead of map() to avoid mongoose versioning error.
Use async.mapSeries() instead of map() to avoid mongoose versioning error.

This fixes #198.

kayaelle/msol-badger,kayaelle/msol-badger,mozilla/openbadger,bdgio/msol-site,bdgio/msol-site,mozilla/openbadger,bdgio/msol-site,kayaelle/msol-badger