private async void AddToGroup(string groupId, User user)
{
if (user.GroupId != default && groupId != user.GroupId)
{
ActiveGroups.RemoveUserFromGroup(user.GroupId, user);
}
if (groupId != user.GroupId)
{
ActiveGroups.AddUserToGroup(groupId, user);
}
await Groups.AddToGroupAsync(user.ConnectionId, groupId);
}
