Added explaination

models/confirmKey.php

@@ -21,6 +21,7 @@ class confirmKey extends \lithium\data\Model {
 
 		//Checks if the key is valid (in the database);
 		Validator::add('isValidKey', function($key) {
+			//If one key is found that matches the input key, then it's legit
 			return confirmKey::count(array('conditions' => compact('key'))) == 1;
 		});
 	}