Enable Rubocop Performance/ReverseEachsh-rubocop-reverse-each

`Array.reverse_each` is faster than `Array.reverse.each` because:

* reverse.each creates a new array then loops each element
* reverse_each loops in reverse order (no intermediate array created)

1 files changed, 1 insertions, 1 deletions

diff --git a/db/migrate/20190222051615_add_indexes_for_merge_request_diffs_query.rb b/db/migrate/20190222051615_add_indexes_for_merge_request_diffs_query.rb
index 0048268ca6f..bf7f7b44dec 100644
--- a/db/migrate/20190222051615_add_indexes_for_merge_request_diffs_query.rb
+++ b/db/migrate/20190222051615_add_indexes_for_merge_request_diffs_query.rb
@@ -35,7 +35,7 @@ class AddIndexesForMergeRequestDiffsQuery < ActiveRecord::Migration[5.0]
   end
 
   def down
-    INDEX_SPECS.reverse.each do |spec|
+    INDEX_SPECS.reverse_each do |spec|
       remove_concurrent_index(*spec)
     end
   end