Groups.destroy can take an array of groupnames
Groups.leave can take an array of groupnames
db.incrObjectField/decrObjectField can take an array of keys
db.sortedSetRemove can take an array of keys and values
db.setRemove can take an array of keys
new method emptydb
use emptydb instead of flushdb, flushdb removes indices for mongo which
breaks search tests
initialize meta.config properly in tests
enable nodebb-plugin-dbsearch for tests