diff --git a/db/migrate/20161220091118_add_index_on_issues_parent_id.rb b/db/migrate/20161220091118_add_index_on_issues_parent_id.rb
new file mode 100644
index 000000000..1cc94b098
--- /dev/null
+++ b/db/migrate/20161220091118_add_index_on_issues_parent_id.rb
@@ -0,0 +1,5 @@
+class AddIndexOnIssuesParentId < ActiveRecord::Migration
+  def change
+    add_index :issues, :parent_id
+  end
+end