public async Task StopChannel()
{
var channelId = Context.User.FindFirst("ChannelId").Value;
var channel = await _applicationDbContext.Channels.FindAsync(channelId);
channel.ChannelEnded = true;
channel.LastUpdate = DateTime.Now;
await _applicationDbContext.SaveChangesAsync();
await _userHubContext.SendChannelEnded(channelId);
}