Drop nodes.external_url

The column moved to page.rb and was now written only by publish_draft!
and by the chapter seed, and read by nothing.

lib/tasks/pages.rake goes with it. backfill_external_url reads the dropped
column. backfill_address is spent and no longer safe to re-run.

1 files changed, 5 insertions, 0 deletions

diff --git a/db/migrate/20260809135746_remove_external_url_from_nodes.rb b/db/migrate/20260809135746_remove_external_url_from_nodes.rb
new file mode 100644
index 00000000..0510d053
--- /dev/null
+++ b/db/migrate/20260809135746_remove_external_url_from_nodes.rb
@@ -0,0 +1,5 @@
+class RemoveExternalUrlFromNodes < ActiveRecord::Migration[8.1]
+  def change
+    remove_column :nodes, :external_url, :string
+  end
+end