Add missing monolog requirement

Author: Seldaek

composer.json

@@ -19,6 +19,7 @@
     "require": {
         "php": ">=5.3.2",
         "symfony/monolog-bridge": "self.version"
+        "monolog/monolog": "1.*"
     },
     "autoload": {
         "psr-0": { "Symfony\\Bundle\\MonologBundle": "" }