fix the build

fix the build

diff --git a/db/migrate/20190523093215_add_topic_id_to_user_exports.rb b/db/migrate/20190523093215_add_topic_id_to_user_exports.rb
index b107e20..a6288ab 100644
--- a/db/migrate/20190523093215_add_topic_id_to_user_exports.rb
+++ b/db/migrate/20190523093215_add_topic_id_to_user_exports.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class AddTopicIdToUserExports < ActiveRecord::Migration[5.2]
   def up
     add_column :user_exports, :topic_id, :integer

GitHub sha: 2e3b74c3