Add manager controller for bill signatures

app/fields/attachment_field.rb

@@ -0,0 +1,11 @@
+require "administrate/field/base"
+
+class AttachmentField < Administrate::Field::Base
+  def to_s
+    data.filename.to_s
+  end
+
+  def blob_path
+    Rails.application.routes.url_helpers.rails_blob_path(data)
+  end
+end