text: const mongoose = require('mongoose')
  
  const username = process.env.MONGODB_USERNAME
  const password = process.env.MONGODB_PASSWORD
  const dbName = process.env.MONGODB_DATABASE
  let connectionString = process.env.MONGODB_CONNECTION_STRING
  
  if (!connectionString) {
    connectionString = `mongodb+srv://${username}:${password}@cluster0.zr7f6.mongodb.net/${dbName}?retryWrites=true&w=majority`
  }
  
  mongoose.set('debug', true)
  
  mongoose
    .connect(connectionString, {
      useNewUrlParser: true,
      useUnifiedTopology: true,
    })
    .then(() => console.log('connection established'))
    .catch(console.log)
  
  module.exports = mongoose.connection
  