Install client for airbrake (errbit) for express application

app.js

const airbrake = require('airbrake').createClient("your project ID", "your api key")
// errbit run on localhost
airbrake.protocol = 'http'
airbrake.serviceHost = 'localhost:3001'
// By default only the errors from the production environment will get reported
// If you put 'production' in airbrake.env, errors will reported
airbrake.env = 'production'

// routing
app.use('/', index)
app.use('/users', users)

// airbrake error handler
app.use(airbrake.expressHandler())