add rules for new CakePHP 3

CakePHP.gitignore

@@ -1,3 +1,12 @@
+CakePHP 3
+
+/vendor/*
+/config/app.php
+/tmp/*
+/logs/*
+
+CakePHP 2
+
 tmp/*
 [Cc]onfig/core.php
 [Cc]onfig/database.php