Updated Power Ups (markdown)

Power-Ups.md

@@ -3,3 +3,34 @@
 Feature available from 1.8.5+
 
 For the moment you can check [this example plugin](https://github.com/filoghost/HolographicDisplays/blob/master/Example_PowerUps/src/com/gmail/filoghost/test/PowerUps.java) to learn how to create power ups.
+
+A power up is very simple, is made of a floating item (the icon) and a hologram. You can assign a PickupHandler to the floating item, that is triggered when a player is near. If you want, you can use [this](...) helper class in your plugin.
+
+**Example**: a power up that gives fire resistance when is collected.
+``` java
+String text = ChatColor.GOLD  + "" + ChatColor.BOLD + "Fire Resistance"
+Location where = ... // Suppose you have a random location in your minigame
+FloatingItem floatingItem = HolographicDisplaysAPI.createFloatingItem(this, where.add(0.0, 0.2, 0.0), new ItemStack(Material.SUGAR));
+final Hologram hologram = HolographicDisplaysAPI.createHologram(this, where.add(0.0, 0.6, 0.0), text);
+
+floatingItem.setPickupHandler(new PickupHandler() {	
+
+	@Override
+	public void onPickup(FloatingItem floatingItem, Player player) {
+					
+		// Play a sound.
+		player.playSound(player.getLocation(), Sound.LEVEL_UP, 1F, 2F);
+					
+		// Play an effect.
+		player.playEffect(floatingItem.getLocation(), Effect.MOBSPAWNER_FLAMES, null);
+					
+		// 1 minute of fire resistance.
+		player.addPotionEffect(new PotionEffect(PotionEffectType.FIRE_RESISTANCE, 60 * 20, 1));
+					
+		// Delete the hologram and the floating item.
+		floatingItem.delete();
+		hologram.delete();
+					
+	}
+});
+```