collection.ensureIndex is deprecated

                                    mongoose.connect(
  url,
  {useCreateIndex: true },
  () => {
    console.log("MongoDB is connected!");
  }
);

                                    /*As of this edit, Mongoose is now at v5.4.13. Per their docs, these are the fixes for the deprecation warnings..*/
mongoose.set('useNewUrlParser', true);
mongoose.set('useFindAndModify', false);
mongoose.set('useCreateIndex', true);

                                    mongoose.set('useNewUrlParser', true);
mongoose.set('useFindAndModify', false);
mongoose.set('useCreateIndex', true);

                                    mongoose.set('useCreateIndex', true);