added raspberry-pi instructions

docs/raspberry-pi.md

@@ -0,0 +1,31 @@
+# Raspberry Pi and Raspbian
+
+It is possible to run the web editor or [command line interface](/cli) from Raspbian on Raspberry Pi 2 or 3.
+
+## Web editor
+
+The web editor requires to install IceWeasel (Firefox) as the built-in browser cannot handle it.
+
+```
+sudo apt-get install iceweasel
+```
+
+Once installed simply navigate to https://codethemicrobit.com or type
+
+```
+firefox https://codethemicrobit.com
+``` 
+
+## Command line
+
+The PXT command line also works on Raspbian and allows to run a local server and/or edit programs from any text editor.
+
+* Node.JS 6.0 needs installed
+
+To install all the tools, 
+
+```
+git clone https://github.com/Microsoft/pxt-rpi.git
+cd pxt-rpi
+sh ./install.sh
+```