Merge branch 'patch-28' into 'master'

Add link to Profiling doc to README

See merge request gitlab-org/gitlab-ce!21345

doc/development/README.md

@@ -54,6 +54,7 @@ description: 'Learn how to contribute to GitLab.'
 - [Performance guidelines](performance.md)
 - [Merge request performance guidelines](merge_request_performance_guidelines.md)
   for ensuring merge requests do not negatively impact GitLab performance
+- [Profiling](profiling.md) for profiling a URL
 
 ## Database guides