How to use arachni in kali

As I can not find arachni in kali, so I download it form here,

when I want to use it, the command shows that

ruby: /lib/i386-linux-gnu/i686/cmov/libc.so.6: version `GLIBC_2.15' not found (required by /root/Desktop/arachni-0.4.2-0.4/bin/../system/usr/lib/libruby.so.1.9)


so I need to update GLIBC to 2.15.

after google a while, I find these

http://stackoverflow.com/questions/10863613/how-to-upgrade-glibc-from-version-2-13-to-2-15-on-debian

http://packages.debian.org/zh-cn/sid/i386/libc6-amd64/download

As my kali runs in i386 and I am in china, so I add 

"deb http://ftp.cn.debian.org/debian sid main" in /etc/apt/sources.list

then run apt-get update && apt-get dist-upgrade.

after that I can use arachni.