public ActionResult Facets(string id)
{
var facets = DocumentSession.Query
<RecentPopularTagsMapOnly.ReduceResult, RecentPopularTagsMapOnly>()
.Where(x => x.LastSeen > DateTime.UtcNow.AddMonths(-1).ToUtcToday())
.ToFacets("Raven/Facets/Tags");
return Json(facets, JsonRequestBehavior.AllowGet);
}