Make rubocop happy.

Make rubocop happy.

diff --git a/app/controllers/admin/email_controller.rb b/app/controllers/admin/email_controller.rb
index 8325070..2415546 100644
--- a/app/controllers/admin/email_controller.rb
+++ b/app/controllers/admin/email_controller.rb
@@ -57,8 +57,8 @@ class Admin::EmailController < Admin::AdminController
           *tuples
         )
         .pluck(:post_id, :user_id, "reply_key::text")
-        .each do |post_id, user_id, reply_key|
-          reply_keys[[post_id, user_id]] = reply_key
+        .each do |post_id, user_id, key|
+          reply_keys[[post_id, user_id]] = key
         end
     end

GitHub sha: c2bca9ca