Update Mongoose initialization

src/app.ts

@@ -34,7 +34,7 @@ const app = express();
 const mongoUrl = MONGODB_URI;
 (<any>mongoose).Promise = bluebird;
 
-mongoose.connect(mongoUrl, { useMongoClient: true }).then(
+mongoose.connect(mongoUrl, { useNewUrlParser: true} ).then(
   () => { /** ready to use. The `mongoose.connect()` promise resolves to undefined. */ },
 ).catch(err => {
   console.log("MongoDB connection error. Please make sure MongoDB is running. " + err);