fix app starting before the bundle has been written

index.js

@@ -76,7 +76,7 @@ app.on('ready', () => {
   if (env.NODE_ENV !== 'production') {
     const browserify = require('./lib/browserify')
     const b = browserify({ watch: true })
-    b.once('bundle', onReady)
+    b.once('written', onReady)
   } else {
     onReady()
   }

lib/browserify.js

@@ -52,6 +52,7 @@ module.exports = opts => {
     b.bundle().pipe(concat(js => {
       fs.writeFile(`${__dirname}/../bundle.js`, js, err => {
         if (err) throw err
+        b.emit('written')
         process.stderr.write('ok!\n')
       })
     }))