public OrderedPostPopulatorSet(
SlugPopulator slug,
TitleAndContentPopulator titleAndContent,
MetaPopulator meta,
PostValidator validator)
{
populators.Add(slug); //Slug first, this will be in the error message, if others throw.
populators.Add(titleAndContent);
populators.Add(meta);
populators.Add(validator); //Validator last, to see if the read values, satisfy the ValidationAttributes
}