Replace groupService's outdated member tracker with deviceService.trackGroup().

lib/db/api.js

@@ -34,10 +34,10 @@ dbapi.loadUser = function(email) {
   return db.run(r.table('users').get(email))
 }
 
-dbapi.loadGroupMembers = function(email) {
+dbapi.loadGroup = function(email) {
   return db.run(r.table('devices').getAll(email, {
-      index: 'ownerEmail'
-    })('serial'))
+    index: 'ownerEmail'
+  }))
 }
 
 dbapi.saveDeviceLog = function(serial, entry) {