pre-receive gist hook, shared repository

pre-receive

#!/bin/bash

# this pre-receive hook returns error when you are trying to push your silly code to the PRODUCTION branch not being member of repo administrators group 

REPOADMINGROUP='repo-admin'
GROUPS_=`groups`
PRODUCTIONBRANCH='master'

while read oldsha newsha REFNAME; do
  
  # GROUPS_ line doesn't contain REPOADMINGROUP and REFNAME contains PRODUCTIONBRANCH
  if [[ $GROUPS_ != *$REPOADMINGROUP* ]] && [[ $REFNAME == *PRODUCTIONBRANCH* ]]; then
    echo pre-receive check ERROR: refname: $REFNAME - you are NOT ALLOWED to push to this branch
    exit 255
  else
    echo pre-receive check OK
  fi
    
done

Hi, where did you place this hooks in GitHUb?