text: let MongoClient = require('mongodb').MongoClient;
  
  let MONGO_URL = "";
  
  let mongo = null;
  
  /**
   * @returns MongoDB instance
   */
  let getDB = async () => {
  	if(!mongo) {
  		mongo = new MongoClient(
  			MONGO_URL,
  			{
  				useNewUrlParser: true,
  				useUnifiedTopology: true
  			}
  		);
  
  		await mongo.connect();
  	}
  
  	return mongo.db('bgm');
  }
  
  module.exports = getDB;