Gulp build task does not include vendor JS files

I think a quick solution would be to change line 85 in the gulpfile.js

```
applicationJavaScriptFiles = config.assets.js;
```

```
applicationJavaScriptFiles= config.assets.lib.js.concat(config.assets.js);
```

Probably no need to code a separate task that allows a build irrespective of the env mode.
