add dynamic documents

db/migrate/20260216162053_create_dynamic_document_versions.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class CreateDynamicDocumentVersions < ActiveRecord::Migration[8.1]
+  def change
+    create_table :dynamic_document_versions do |t|
+      t.references :dynamic_document, null: false, foreign_key: true, index: false
+      t.string :sha1, null: false
+      t.text :areas, null: false
+
+      t.timestamps
+    end
+
+    add_index :dynamic_document_versions, %i[dynamic_document_id sha1], unique: true
+  end
+end