//Create new user to db with hashed password and password salt
        public async Task <User> RegisterAsync(User user, string password)
        {
            byte[] passwordHash, passwordSalt;

            HashPassword(password, out passwordHash, out passwordSalt);

            user.PasswordSalt = passwordSalt;
            user.PasswordHash = passwordHash;

            await _context.AddAsync(user);

            await _context.SaveChangesAsync();

            return(user);
        }
 //Save all changes to database
 public async Task <bool> SaveAll()
 {
     return(await _context.SaveChangesAsync() > 0);
 }