Make sure only groups can create if set

Signed-off-by: Julius Härtl <jus@bitgrid.net>

lib/Service/PermissionService.php

@@ -248,13 +248,16 @@ class PermissionService {
 
 	public function canCreate() {
 		$groups = $this->getGroupLimitList();
+		if (count($groups) === 0) {
+			return true;
+		}
 		foreach ($groups as $group) {
 			if ($this->groupManager->isInGroup($this->userId, $group)) {
-				return false;
-			}
-		}
 				return true;
 			}
+		}
+		return false;
+	}
 
 	private function getGroupLimitList() {
 		$value = $this->config->getAppValue('deck', 'groupLimit', '');