TableSync doesn't work if hook was used in model

TableSync defines hooks directly in model without including or prepending code and if you define similar hooks, tablesync's hooks are shadowed and don't work

```rb
class Test < Sequel::Model
  TableSync.sync(self)

  def after_create
    super
    p "AFTER CREATE"
  end
end

Test.create
```

You will see "AFTER CREATE" in console but data won't be synced