Light it up - use photo resistor to light LED automatically in darkness

lightitup.ino

#define LED 8
#define PHOTORESISTOR A0
#define THRESHOLD 200

void setup()
{
  Serial.begin(9600);
  pinMode(LED, OUTPUT);
  pinMode(PHOTORESISTOR, INPUT_PULLUP);
  Serial.println("Hello, Arduino");
}

void loop()
{
  int darkness = analogRead(PHOTORESISTOR);
  if (darkness > THRESHOLD) {
  	digitalWrite(LED, HIGH);
    delay(20);
    digitalWrite(LED, LOW);
  }
}