docs(migrate): Updated migrate (#2834)

* updated 4.md

Made certain changes to the document that I thought was necessary. Added more links to installation guides and about plugins. 

This is in regards to the issue [#1934](#1934)

* updated 4.md

* requested changes to 4.md

* Update src/content/migrate/4.md

Co-Authored-By: Eugene Hlushko <[email protected]>

* Update src/content/migrate/4.md

Co-Authored-By: Eugene Hlushko <[email protected]>

* updated 4.md with requested changes

* updated 4.md

* Update src/content/migrate/4.md

Co-Authored-By: Eugene Hlushko <[email protected]>

Author: 2 people

src/content/migrate/4.md

@@ -4,6 +4,14 @@ sort: 1
 contributors:
   - sokra
   - EugeneHlushko
+  - Kolhar730
+related:
+  - title: 'To v2 or v3 from v1'
+    url: https://webpack.js.org/migrate/3/
+  - title: 'RIP CommonChunkPlugin'
+    url: https://gist.github.com/sokra/1522d586b8e5c0f5072d7565c2bee693
+  - title: 'webpack 4: migration guide for plugins/loaders'
+    url: https://medium.com/webpack/webpack-4-migration-guide-for-plugins-loaders-20a79b927202
 ---
 
 This guide only shows major changes that affect end users. For more details please see [the changelog](https://github.com/webpack/webpack/releases).
@@ -12,22 +20,26 @@ This guide only shows major changes that affect end users. For more details plea
 ## Node.js v4
 
 If you are still using Node.js v4 or lower, you need to upgrade your Node.js installation to Node.js v6 or higher.
-
+ 
+Instructions for upgrading your Node.js version can be found [here](https://stackoverflow.com/questions/10075990/upgrading-node-js-to-latest-version). 
 
 ## CLI
 
 The CLI has moved to a separate package: webpack-cli. You need to install it before using webpack, see [basic setup](/guides/getting-started/#basic-setup).
 
+The installation guide can be found [here](/guides/installation).
+
 
 ## Update plugins
 
-Many 3rd-party plugins need to be upgraded to their latest version to be compatible.
+Many 3rd party plugins need to be updated to the latest versions to be compatible with webpack 4. Links to popular plugins can be found [here](https://github.com/webpack-contrib/awesome-webpack#webpack-plugins).
 
 
 ## mode
 
 Add the new [`mode`](/configuration/mode/) option to your config. Set it to production or development in your configuration depending on config type.
 
+
 __webpack.config.js__
 
 ``` diff
@@ -37,7 +49,7 @@ module.exports = {
 }
 ```
 
-Alternatively you can pass it via CLI: `--mode production`/`--mode development`
+T> The purpose of `development` mode and `production` mode is different. You can use `webpack-merge` as shown in [production guide](/guides/production/#setup) to optimize configurations.
 
 ## Deprecated/Removed plugins
 
@@ -156,3 +168,4 @@ module.exports = {
 ## module.loaders
 
 `module.loaders` were deprecated since webpack 2 and are now removed in favor of [`module.rules`](/configuration/module/#rule).
+