Update index.md

Author: ivan-hc

index.md

@@ -338,6 +338,7 @@ am -i --user topgrade
 - *[ArchImage](https://github.com/ivan-hc/ArchImage), create AppImages for all distributions using Arch Linux packages. Powered by JuNest*
 - *[Firefox for Linux scripts](https://github.com/ivan-hc/Firefox-for-Linux-scripts), easily install the official releases of Firefox for Linux*
 - *[My AppImage packages](https://github.com/ivan-hc#my-appimage-packages) the complete list of packages managed by me and available in this database*
+- *[portable2appimage](https://github.com/ivan-hc/portable2appimage), convert standalone, self-contained portable apps into AppImage packages*
 - *[Snap2AppImage](https://github.com/ivan-hc/Snap2AppImage), try to convert Snap packages to AppImages*
 
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