Use Pimple instead of Core\Registry and add Monolog for logging

app/ServiceProvider/Logging.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace ServiceProvider;
+
+use Pimple\Container;
+use Pimple\ServiceProviderInterface;
+use Monolog\Logger;
+use Monolog\Handler\StreamHandler;
+use Monolog\Handler\SyslogHandler;
+
+class Logging implements ServiceProviderInterface
+{
+    public function register(Container $container)
+    {
+        $logger = new Logger('app');
+        $logger->pushHandler(new StreamHandler(__DIR__.'/../../data/debug.log', Logger::DEBUG));
+        $logger->pushHandler(new SyslogHandler('kanboard', LOG_USER, Logger::DEBUG));
+
+        $container['logger'] = $logger;
+    }
+}