fix

_contao_backup/contao_backup.php

@@ -37,7 +37,7 @@ if (count($backupFileNames) > NUM_BACKUPS) {
 
 $b = __DIR__;
 $parentDir = substr(__DIR__, 0, strlen($curDirName) * -1);
-$shellCommand = 'mysqldump --user=' . DATABASE_USER . ' --password="' . DATABASE_PASS . '" ' . DATABASE_NAME . ' > dump.sql';
+$shellCommand = "mysqldump --user=" . DATABASE_USER . " --password='" . DATABASE_PASS . "' " . DATABASE_NAME . " > dump.sql";
 shell_exec($shellCommand);
 
 $zip = new ZipArchive();