Added missing RendererInterface

src/TemplateRenderer/AbstractRenderer.php

@@ -10,7 +10,7 @@
  */
 namespace League\OAuth2\Server\TemplateRenderer;
 
-abstract class AbstractRenderer
+abstract class AbstractRenderer implements RendererInterface
 {
     /**
      * @var string

src/TemplateRenderer/RendererInterface.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace League\OAuth2\Server\TemplateRenderer;
+
+interface RendererInterface
+{
+    /**
+     * Render login template.
+     *
+     * @param array $data
+     *
+     * @return string
+     */
+    public function renderLogin(array $data = []);
+
+    /**
+     * Render authorize template.
+     *
+     * @param array $data
+     *
+     * @return string
+     */
+    public function renderAuthorize(array $data = []);
+}