Merge pull request #707 from github/add-github-topic

Add GitHub topic

Author: kenyonj

topics/github/github.png

@@ -0,0 +1,13 @@
+---
+created_by: Chris Wanstrath, PJ Hyett, Tom Preston-Werner, and Scott Chacon
+display_name: GitHub
+github_url: https://github.com/github
+logo: github.png
+released: April 10, 2008
+short_description: You’re lookin’ at it.
+topic: github
+related: git
+url: https://github.com
+wikipedia_url: https://en.wikipedia.org/wiki/GitHub
+---
+GitHub makes it easier for developers to be developers: to work together, to solve challenging problems, to create the world’s most important technologies.