I just tried installing it using the ruby command but somehow the dependencies are not resolved hence brew does not completely install. But, try installing by cloning:
git clone https://github.com/Homebrew/linuxbrew.git ~/.linuxbrew
and then add the following to your .bash_profile
:
export PATH="$HOME/.linuxbrew/bin:$PATH"
export MANPATH="$HOME/.linuxbrew/share/man:$MANPATH"
export INFOPATH="$HOME/.linuxbrew/share/info:$INFOPATH"
It should work..