Add content for ORM (#3060)

* Update readme.md

* Update content/roadmaps/116-aspnet-core/content/104-orm/readme.md

* Update content/roadmaps/116-aspnet-core/content/104-orm/readme.md

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/116-aspnet-core/content/104-orm/readme.md

@@ -1 +1,5 @@
-# Orm
+# ORM
+
+ORM stands for Object-Relational Mapping, and it is a technique that allows a developer to work with a database using objects. It is a way of abstracting the database so that the developer can think in terms of objects, rather than tables and SQL queries. This can make it easier to write and maintain code, as well as improve the performance of the application.
+
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.telerik.com/blogs/dotnet-basics-orm-object-relational-mapping'>ORM (Object Relational Mapping)</BadgeLink>