public RedirectToActionResult AddExistingArtist(string artistName)
{
Artist artist = (from s in repo.Shows
from a in s.Artists
where a.Name.ToLower() == artistName.ToLower()
select a).Single();
Show show = repo.Shows.OrderByDescending(s => s.ShowID).First();
repo.AddArtist(show, artist);
//show.Artists.Add(artist);
return(RedirectToAction("AddArtist"));
}