Update Prestashop.gitignore

Prestashop.gitignore

@@ -7,7 +7,14 @@ config/settings.*.php
 # The following files are generated by PrestaShop.
 
 admin-dev/autoupgrade/
-/cache/*
+/cache/
+!/cache/index.php
+!/cache/cachefs/index.php
+!/cache/purifier/index.php
+!/cache/push/index.php
+!/cache/sandbox/index.php
+!/cache/smarty/index.php
+!/cache/tcpdf/index.php
 config/xml/*.xml
 /log/*
 *sitemap.xml