Much base work started

db/migrate/20251029120528_update_external_ids_from_architecture.rb

@@ -0,0 +1,16 @@
+class UpdateExternalIdsFromArchitecture < ActiveRecord::Migration[8.1]
+  def change
+    change_table :external_ids do |t|
+      # Make source and value required
+      t.change_null :source, false
+      t.change_null :value, false
+    end
+
+    # Add indexes as specified in architecture
+    # Ensure each source only appears once per work
+    add_index :external_ids, [:work_id, :source], unique: true
+
+    # Fast lookup by external ID (for "find work by IMDB ID" queries)
+    add_index :external_ids, [:source, :value], unique: true
+  end
+end