raspbian.txt

Expand Filesystem, OK
Advanced Options, Hostname
Advanced Options, SSH, Enable, OK
Advanced Options, Update
Finish

$ sudo reboot
user:pi pass:raspberry
$ sudo vi /etc/network/interfaces

# iface eth0 inet dhcp
iface eth0 inet static
address 192.168.100.191
netmask 255.255.255.0
gateway 192.168.100.254

$ sudo reboot

$ vi ~/.ssh/config

Host nfs
  User pi
  Hostname 192.168.100.191

$ ssh-copy-id nfs
$ ssh nfs
$ sudo sed -i -e 's/wheezy/jessie/g' /etc/apt/source.list
$ sudo apt-get update -y
$ sudo apt-get dist-upgrade -y
ssh root disable, NO
after all YES
sudo apt-get install ruby1.9.1-dev