Update README including frond-end section

README.md

@@ -245,6 +245,22 @@ To view Modules and API Reference documentation:
 2. View the generated docs.  
 `open doc/index.html`
 
+## Front-end 
+
+### Javascript
+
+All Javascript files are under [apps/block_scout_web/assets/js](https://github.com/poanetwork/blockscout/tree/master/apps/block_scout_web/assets/js) and the main file is [app.js](https://github.com/poanetwork/blockscout/blob/master/apps/block_scout_web/assets/js/app.js). This file imports all javascript used in the application. If you want to create a new JS file consider creating into [/js/pages](https://github.com/poanetwork/blockscout/tree/master/apps/block_scout_web/assets/js/pages) or [/js/lib](https://github.com/poanetwork/blockscout/tree/master/apps/block_scout_web/assets/js/lib), as follows:
+
+#### js/lib
+This folder contains all scripts that can be reused in any page or can be used as a helper to some component.
+
+#### js/pages
+This folder contains the scripts that are specific for some page.
+
+#### Redux
+This project uses Redux to control the state in some pages. There are pages that have things happening in real-time thanks to the Phoenix channels, e.g. Address page, so the page state changes a lot depending on which events it is listening. The redux is also used to load some contents asynchronous, see [async_listing_load.js](https://github.com/poanetwork/blockscout/blob/master/apps/block_scout_web/assets/js/lib/async_listing_load.js).
+
+To understand how to build new pages that need redux in this project, see the [redux_helpers.js](https://github.com/poanetwork/blockscout/blob/master/apps/block_scout_web/assets/js/lib/redux_helpers.js)
 
 ## Internationalization