Added routes PUT to the default list (doc updates).

Author: ashiksp

guides/source/getting_started.md

@@ -712,6 +712,7 @@ $ bin/rails routes
              POST   /articles(.:format)          articles#create
 edit_article GET    /articles/:id/edit(.:format) articles#edit
              PATCH  /articles/:id(.:format)      articles#update
+             PUT    /articles/:id(.:format)      articles#update
              DELETE /articles/:id(.:format)      articles#destroy
 ```