Merge pull request #4069 from shaedrich/api

Add related to topic "API"

Author: ahpook

topics/api/index.md

@@ -5,5 +5,6 @@ short_description: An API (Application Programming Interface) is a collection of
   and subroutines for building software.
 topic: api
 wikipedia_url: https://en.wikipedia.org/wiki/Application_programming_interface
+related: rest-api, graphql-api, soap, rpc, wsdl
 ---
-An API can be thought of as an instruction manual for communication between multiple software apparatuses. For example, an API may be used for database communication between web applications. By extracting the implementation and relinquishing data into objects, an API simplifies programming.
+An **API** can be thought of as an instruction manual for communication between multiple software apparatuses. For example, an API may be used for database communication between web applications. By extracting the implementation and relinquishing data into objects, an API simplifies programming.