public User Authenticate(string username, string password)
{
User user = _context.Users.SingleOrDefault(u => u.Username == username && u.Password == password);
if (user is null)
{
return(null);
}
var token = _jwtSettings.TokenHandler.CreateToken(_jwtSettings.GetTokenDescriptor(user.Id.ToString(), user.Role));
user.Token = _jwtSettings.TokenHandler.WriteToken(token);
return(user);
}