Merge branch 'docs_vlad_es_quotes' into 'master'

Corrected expression to include correct quotes in ES Integration

See merge request gitlab-org/gitlab!21418

doc/integration/elasticsearch.md

@@ -524,7 +524,7 @@ Here are some common pitfalls and how to overcome them:
 
   ```ruby
   u = User.find_by_username('your-username')
-  s = SearchService.new(u, {:search => 'search_term', :scope => ‘blobs’})
+  s = SearchService.new(u, {:search => 'search_term', :scope => 'blobs'})
   pp s.search_objects.to_a
   ```