message: set assetPrefix in next.config.js to NOW_URL
diff: @@ -3,6 +3,12 @@ const sass = require('@zeit/next-sass')
  const mdx = require('@zeit/next-mdx')({extension: /\.mdx?$/})
  module.exports = withPlugins([sass, mdx], {
  + /*
  + * Note: Prefixing assets with the fully qualified deployment URL
  + * makes them available even when the site is served from a path alias, as in
  + * <https://primer.style/components>
  + */
  + assetPrefix: process.env.NOW_URL,
  pageExtensions: ['js', 'jsx', 'md', 'mdx'],
  sassLoaderOptions: {
  includePaths: ['node_modules']
  