template 엔진 '일단' 추가

e_lib/plates/Extension/ExtensionInterface.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace League\Plates\Extension;
+
+use League\Plates\Engine;
+
+/**
+ * A common interface for extensions.
+ */
+interface ExtensionInterface
+{
+    public function register(Engine $engine);
+}