addEntry(name, src) {
        webpackConfig.addEntry(name, src);

        return this;
    }
Adds a JavaScript file that should be webpacked:

```
// final output file will be main.js in the output directory
Encore.addEntry('main', './path/to/some_file.js');
```

If the JavaScript file imports/requires CSS/Sass/LESS files,
then a CSS file (e.g. main.css) will also be output.

@param {string} name          The name (without extension) that will be used
                              as the output filename (e.g. app will become app.js)
                              in the output directory.
@param {string|string[]} src  The path to the source file (or files)
@returns {Encore}