update settings sample

settings-sample.php

@@ -11,6 +11,7 @@ class Settings
 	const TIMEZONE = 'Europe/Paris';
 	const API_KEY = '';
 	const MODE = Spot::MODE_BLOG; //Spot::MODE_HISTO/MODE_BLOG
+	const GOOGLE_MAPS_API_KEY = '';
 	const DEBUG = true;
 }