public IEnumerable<JsonDocument> ScanByTag(string tag)
{
return Storage.Documents["ByTag"]
.SkipTo(new RavenJObject { { "tag", tag } })
.TakeWhile(x => string.Equals(x.Value<string>("tag"), tag, StringComparison.InvariantCultureIgnoreCase))
.Select(token => Read(token.Value<string>("key")))
.Where(read => read != null);
}