Applying man with colour under zsh

After installing zshell and applying the zshrc from grml system-wide, my man page doesn’t want to be colourful. The configuration is caused by a environmental variable GROFF_NO_SGR, when it’s set to 1, man page will be able to paint with colour.

Here is my personal .zshrc:

# Vim key binding
bindkey -v

# The important part.
export GROFF_NO_SGR=1

# PATH to current directory
export PATH=$PATH:.