Update Next.js installation instructions (#250)

README.md

@@ -135,12 +135,14 @@ Now on your `next.config.js` configure your sass to include the directory where
 
 ```javascript
 const withSass = require('@zeit/next-sass')
-const withTM = require('next-transpile-modules');
-
-module.exports = withSass(withTM({
-    transpileModules: ['react-bulma-components'],
-    sassLoaderOptions: {
-        includePaths: ["./src"]
+const withTM = require('next-plugin-transpile-modules');
+
+module.exports = withTM(withSass({
+    transpileModules: ['react-bulma-components'], // Tell next to transpile the react-bulma-components module
+    // NOTE: this also allow to use abolute import from this folder not only for the _variables.sass file
+    webpack: (config, { buildId, dev, isServer, defaultLoaders, webpack }) => {
+        config.resolve.modules.push('./pages'); // Add to webpack configuration the folder where you put the _variables file
+        return config
     },
 }))
 ```