Updated description of Pieman

Add Alpine Linux since Pieman supports it

Author: denismosolov

README.md

@@ -93,7 +93,7 @@ The complete collection of Raspberry Pi models consist of:
 - [P4wnP1](https://github.com/mame82/P4wnP1) - P4wnP1 is a highly customizable USB attack platform, based on a low cost Raspberry Pi Zero or Raspberry Pi Zero W (required for HID backdoor). ![Supports Raspberry Pi Zero](/media/badges/rpi-0.png)
 - [CusDeb](https://cusdeb.com/en/) - Web UI for creating custom images with specific packages installed.
 - [Alpha](https://github.com/farjump/raspberry-pi) - Remotely load, debug and test bare-metal programs using GDB with this system-level GDB server.
-- [Pieman](https://github.com/tolstoyevsky/pieman) - Script for creating custom images based on Raspbian, Devuan and Ubuntu.
+- [Pieman](https://github.com/tolstoyevsky/pieman) - Script for creating custom images based on Raspbian, Devuan, Ubuntu and Alpine Linux.
 - [iotwifi](https://github.com/cjimti/iotwifi) - Wifi AP + Client management in 8MB [Docker Container](https://hub.docker.com/r/cjimti/iotwifi/), with REST API for controlling wifi client and station modes simultaneously. ![Supports Raspberry Pi 3](/media/badges/rpi-3.png)
 - [TorTiPi](https://github.com/r0hi7/tortipi) - Shell script to automate the task of converting Raspberry Pi into a tor based wifi hotspot.