I am new in MongoDB and need a help. In my DB I am trying to create a collection, which has only one document.T hat document has a simple key ` cities, which is an array of 124247 objects. Here is my code 

```
const express = require('express');
const bodyParser = require('body-parser');
const mongoose = require("mongoose");
const cities = require('cities.json');
const Schema = mongoose.Schema;
const db = mongoose.connection;
const app = express();

mongoose.connect("mongodb://localhost:27017/cities");

db.once("open", function() {
  console.log("Connection ok.");
})

const cityScheme = new Schema({
  cities: Array
});

const WorldCities = mongoose.model("WorldCities", cityScheme);
const myCities = new WorldCities({
  cities: cities
}).save().then(data => console.log({}.toString.call(data.cities), 'dataaa'));

WorldCities.find({
  name: "Yerevan"
}, function(err, data) {
  console.log(data, 'Armenia');
});
cityScheme.statics.getSearchedcity = function(res) {
  this.find({}, (err, citysList) => res.json({
    citysList
  }));
}

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
  extended: true
}));

app.get('/api/city', (req, res) => {

})

app.listen(3000);

```

This is the link to cities.json ` [Cities.json](https://github.com/lutangar/cities.json/blob/master/cities.json) .

So here I want to find the city with name Yerevan, but I don't know how to find it.