Created file class with File::extension method, added File to aliases under application

system/file.php

@@ -0,0 +1,16 @@
+<?php namespace System;
+
+class File {
+	
+	/**
+	 * Get a file's extension. 
+	 * 
+	 * @param  string $path
+	 * @return string
+	 */
+	public static function extension($path)
+	{
+		return pathinfo($path, PATHINFO_EXTENSION);
+	}
+
+}