v3 fix tests and use coroutines instead of regenerator

migrations/api_v3/challengesMembers.js

@@ -30,7 +30,7 @@ var MONGODB_NEW = nconf.get('MONGODB_NEW');
 
 var MongoClient = MongoDB.MongoClient;
 
-mongoose.Promise = Bluebird.all; // otherwise mongoose models won't work
+mongoose.Promise = Bluebird; // otherwise mongoose models won't work
 
 // To be defined later when MongoClient connects
 var mongoDbOldInstance;