Add bookmark admin

db/migrate/20230507001217_add_cached_bookmark_to_post.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+ROM::SQL.migration do
+  change do
+    alter_table(:posts) do
+      add_column :cached_content, :text
+    end
+  end
+end