Merge pull request #20 from lbausch/patch-1

Avoid "Undefined index: query" warning

Author: hillelcoren

src/InvoiceNinja/Models/AbstractModel.php

@@ -154,7 +154,7 @@ protected static function sendRequest($url, $data = false, $type = 'GET', $raw =
         ]);
 
         $parsedUrl = parse_url($url);
-        $separator = ($parsedUrl['query'] == NULL) ? '?' : '&';
+        $separator = (!isset($parsedUrl['query']) || $parsedUrl['query'] == NULL) ? '?' : '&';
 
         $url .= $separator . http_build_query($options);