Merge pull request #336 from jowy/patch-1

Fatal error: Class 'Monolog\Handler\Logger' not found in RollbarHandler....

src/Monolog/Handler/RollbarHandler.php

@@ -4,6 +4,7 @@ namespace Monolog\Handler;
 
 use RollbarNotifier;
 use Exception;
+use Monolog\Logger;
 
 /**
  * Sends errors to Rollbar