added wikipedia api

README.md

@@ -103,6 +103,7 @@ A collective list of JSON APIs for use in web development.
 | Chuck Norris Database | Jokes | No | [Go!](http://www.icndb.com/api) |
 | Medium | community of readers and writers offering unique perspectives on ideas. | Yes | [Go!](https://github.com/Medium/medium-api-docs)
 | Flickr | Flickr Services | Yes | [Go!](https://www.flickr.com/services/api/)
+| Wikipedia | A free encyclopedia | No | [Go!](https://www.mediawiki.org/wiki/API:Main_page) |
 
 ### Music
 | API | Description | OAuth |Link |