Added an handler for NewRelic:

* implemented a test which verifies that the fallback handler handles records when the NewRelic PHP extension is not installes
* implemented the actual handler

src/Monolog/Handler/NewRelicHandler.php

@@ -0,0 +1,49 @@
+<?php
+
+/*
+ * This file is part of the Monolog package.
+ *
+ * (c) Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Monolog\Handler;
+
+/**
+ * Base class for all mail handlers
+ *
+ * @author Gyula Sallai
+ */
+class NewRelicHandler extends AbstractProcessingHandler
+{
+    protected $fallbackHandler;
+    
+    /**
+     * {@inheritdoc}
+     */
+    protected function write(array $record)
+    {
+        if (extension_loaded('newrelic')) {
+            newrelic_notice_error($record['message']);
+
+            foreach ($record['context'] as $key => $parameter) {
+                newrelic_add_custom_parameter($key, $parameter);
+            }
+        } elseif ($this->fallbackHandler instanceOf AbstractProcessingHandler) {
+            $this->fallbackHandler->write($record);
+        }
+    }
+
+    /**
+     * Sets the fallback handler to be used to log informations if the New Relic
+     * extension is not available.
+     *
+     * @param Monolog\Handler\AbstractProcessingHandler $handler 
+     */
+    public function setFallbackHandler(AbstractProcessingHandler $handler)
+    {
+        $this->fallbackHandler = $handler;
+    }
+}

tests/Monolog/Handler/NewRelicHandlerTest.php

@@ -0,0 +1,33 @@
+<?php
+
+/*
+ * This file is part of the Monolog package.
+ *
+ * (c) Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Monolog\Handler;
+
+use Monolog\TestCase;
+use Monolog\Logger;
+
+class NewRelicHandlerTest extends TestCase
+{
+    public function testFallbackHandler()
+    {
+        $handler         = new NewRelicHandler();
+        $fallbackHandler = new TestHandler();
+        $handler->setFallbackHandler($fallbackHandler);
+        $record          = array(
+            'level' => Logger::DEBUG,
+            'extra' => array(),
+        );
+        
+        $handler->handle($record);
+        
+        $this->assertCount(1, $fallbackHandler->getRecords());
+    }
+}