LINQ GroupBy DateTime dilemma
public IDictionary<string, int> GetCountByDate(DateTime fromDate, DateTime toDate)
{
    var result = Database.Set<User>().Where(x => x.CreatedAt >= fromDate && x.CreatedAt <= toDate).GroupBy(x => new { x.CreatedAt.Year, x.CreatedAt.Month, x.CreatedAt.Day }).Select(x => new { Date = x.Key, Count = x.Count() });

    return result.ToDictionary(x => new DateTime(x.Date.Year, x.Date.Month, x.Date.Day).ToShortDateString(), x => x.Count);
}

return result.ToDictionary(x => new DateTime(x.Date.Year, x.Date.Month, x.Date.Day).ToLocalTime().ToShortDateString(), x => x.Count);

public IDictionary<string, int> GetCountByDate(DateTime fromDate, DateTime toDate)
{
    DateTime utcFrom = fromDate.ToUniversalTime();
    DateTime utcTo = toDate.ToUniversalTime();
    int offset = (int)(fromDate - utcFrom).TotalHours;
    var result = Database.Set<User>().Where(x => x.CreatedAt >= utcFrom && x.CreatedAt <= utcTo)
        .GroupBy(x => new {
            SqlFunctions.DateAdd("hh", offset, x.CreatedAt).Value.Year,
            SqlFunctions.DateAdd("hh", offset, x.CreatedAt).Value.Month,
            SqlFunctions.DateAdd("hh", offset, x.CreatedAt).Value.Day })
        .Select(x => new { Date = x.Key, Count = x.Count() });

    return result.ToDictionary(x => new DateTime(x.Date.Year, x.Date.Month, x.Date.Day).ToShortDateString(), x => x.Count);
}