Add Witty Pi information

src/en/overlay/witty-pi.md

@@ -0,0 +1,50 @@
+<!--
+---
+name: Witty Pi
+class: board
+type: rtc,switch,power
+formfactor: HAT
+image: 'witty-pi.png'
+manufacturer: UUGear s.r.o.
+description: Realtime clock and power management for Raspberry Pi
+url: http://www.uugear.com/product/witty-pi-realtime-clock-and-power-management-for-raspberry-pi/
+github: https://github.com/uugear/Witty-Pi
+buy: http://www.uugear.com/product/witty-pi-realtime-clock-and-power-management-for-raspberry-pi/
+pincount: 40
+eeprom: no
+power: 5v
+pin:
+  '3':
+    name: SDA
+    mode: i2c
+  '5':
+    name: SCL
+    mode: i2c
+  '7':
+    name: HALT
+    mode: input
+  '11':
+    name: LED
+    mode: output
+  '8':
+    name: TXD
+    mode: other
+i2c:
+  '0x68':
+    name: DS1307
+    device: DS1307
+-->
+# Witty-Pi
+
+Witty Pi is an extension board that adds realtime clock and power management to your Raspberry Pi. You can turn on/off your Raspberry Pi with a single tap on the button on Witty Pi, and the power supply for Raspberry Pi and all its USB peripherals will get fully cut after the shutdown. Witty Pi has a CR2032 backed realtime clock (DS1337) on board, and can keep time for Raspberry Pi when it is off. You can schedule next shutdown/startup of your Pi via the software. A user-defined schedule script could be used for complex use case, which requires scheduling multiple shutdowns and startups at different moments.
+
+You can use the two commands below to install software for Witty Pi:
+
+```bash
+wget http://www.uugear.com/repo/WittyPi/installWittyPi.sh
+
+sudo sh installWittyPi.sh
+```
+After the installation is done, reboot your Raspberry Pi and your Witty Pi is ready to go.
+
+Witty Pi supports all Raspberry Pi models that have 40-pin header, including A+, B+, 2B, 3B and Zero.