public static async Task Clear(this MongoCardStorage mongo)
        {
            foreach (var card in await mongo.GetAllCards())
            {
                await mongo.DeleteCard(card.Id);
            }

            foreach (var collection in await mongo.GetAllCollections())
            {
                await mongo.DeleteCollection(collection.Id);
            }
        }
 public void Init()
 {
     mongo = new MongoCardStorage(context);
 }