Set output publicPath in webpack.config.js

When 'output.publicPath' is not specified in webpack.config.js, it's
assumed that all produced assets (CSS, JS, images) are in the same
directory. That means produced 'index.html' will look for them relative
to itself.

While this is not a problem on its own, it's a problem when one have
nested routes in the application. For instance, if someone will try to
open some path, say,

 /foo/bar/baz

the webserver will respond with 'index.html' that will look for assets
in current directory which is /foo/bar/baz. Obviously, there no such
directory so the webserver won't be able to respond with JS/CSS.

Fortunately, it could be fixed by settings 'output.publicPath' option
that should be considered as a path to assets. When it's set to '/'
the assets will be looked at root domain no matter which path was passed
in URI.

[1] https://webpack.js.org/guides/public-path/

Author: ikalnytskyi

webpack.config.js

@@ -32,6 +32,7 @@ module.exports = () => {
     output: {
       filename: '[name].[chunkhash].js',
       path: path.resolve(__dirname, 'dist'),
+      publicPath: process.env.ASSET_PATH || '/',
     },
 
     module: {