feat(migrate): add AddIndexOnPostsUserId, down and AddSlugToPosts

examples/blog/db/migrate/20260907000011_add_featured_to_posts.rb

@@ -0,0 +1,9 @@
+class AddFeaturedToPosts < Prism::Orm::Migration
+  def up
+    add_column :posts, :featured, default: false
+  end
+
+  def down
+    remove_column :posts, :featured
+  end
+end