Update index.md

docs/en/tutorials/modular-crm/index.md

@@ -13,4 +13,8 @@ This tutorial is organized as the following parts:
 
 ## Download the Source Code
 
-*TODO*
+You can download the completed sample solution [here](https://github.com/abpframework/abp-samples/tree/master/ModularCRM).
+
+## See Also
+
+* [Book Store: Web Application Development Tutorial](../book-store/index.md)