Add code flow wiki page.

Code-Flow.md

@@ -0,0 +1,39 @@
+> **CONTENT**
+
+- [Overview](#overview)
+- [Code Flow](#Code-Flow)
+    - [User Registration](#User-Registration)
+    - [User Login](#grpc)
+    - [Add Item To Cart](#api-gateways)
+    - [Order Creation](#internal-architectural-patterns)
+
+## Overview
+
+This page covers the interaction between different components in  `eShopOnContainers`. Set up the code base in your local if you haven't done already :
+
+- Setup your development system for [Windows](Windows-setup) or [Mac](Mac-setup)
+
+Different functionalities of **eShopOnContainers** application has been captured in the following diagrams.
+
+## Code Flow
+
+>**IMPORTANT:** All the following interaction has been captured taking **Web.MVC** as reference. It may subject to change for **Web.SPA**
+
+### User Registration
+
+![](images/Code-Flow/user-registration.png)
+
+
+### User Login
+
+![](images/Code-Flow/user-login.png)
+
+
+### Add Item To Cart
+
+![](images/Code-Flow/add-item-to-cart.png)
+
+
+### Order Creation
+
+![](images/Code-Flow/order-creation.png)

_Sidebar.md

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 - [Architecture](Architecture)
   - [BFF implementation](BFF-implementation)
+  - [Code Flow](Code-Flow)
 - [Application](Explore-the-application)
 - [Code](Explore-the-code)
   - [Simplified CQRS & DDD](Simplified-CQRS-and-DDD)