Add API brief description (#1196)

* Add API brief description

* Update content/roadmaps/101-backend/content/109-apis/readme.md

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

content/roadmaps/101-backend/content/109-apis/readme.md

@@ -1 +1,6 @@
-# Apis
+# APIs
+
+API is the acronym for Application Programming Interface, which is a software intermediary that allows two applications to talk to each other.
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://aws.amazon.com/what-is/api/'>What is an API?</BadgeLink>