diff --git a/db/migrate/20170207050700_add_index_on_disk_filename_to_attachments.rb b/db/migrate/20170207050700_add_index_on_disk_filename_to_attachments.rb
new file mode 100644
index 000000000..6f41a9c4b
--- /dev/null
+++ b/db/migrate/20170207050700_add_index_on_disk_filename_to_attachments.rb
@@ -0,0 +1,5 @@
+class AddIndexOnDiskFilenameToAttachments < ActiveRecord::Migration
+  def change
+    add_index :attachments, :disk_filename
+  end
+end