Add check for curl ext

src/Monolog/Handler/LogglyHandler.php

@@ -27,6 +27,10 @@ class LogglyHandler extends AbstractProcessingHandler
 
     public function __construct($token, $level = Logger::DEBUG, $bubble = true)
     {
+        if (!extension_loaded('curl')) {
+            throw new \LogicException('The curl extension is needed to use the LogglyHandler');
+        }
+
         $this->token = $token;
 
         parent::__construct($level, $bubble);