Git lab references post commit hook

post-commit

#!/bin/sh

PRIVATE_TOKEN="YOU_SECRET_TOKEN"
GITLAB_URL="http://gitlab.example.com/"

URL=`git config --get remote.origin.url`
PROJECT=`basename ${URL} .git | cut -d':' -f2`

COMMIT_MSG="git log -1 HEAD"
COMMIT_HASH_MSG=`git log -1 HEAD | head -1`

for issue_id in `${COMMIT_MSG} | grep -o -e "\(closes\|fixes\) #[0-9]\+" | cut -d'#' -f2`; do
    curl -X POST -d "body=fixed in ${COMMIT_HASH_MSG}" \
        ${GITLAB_URL}api/v3/projects/${PROJECT}/issues/${issue_id}/notes/?private_token=${PRIVATE_TOKEN}
done

for issue_id in `${COMMIT_MSG} | grep -o -e "\(re\|refs\) #[0-9]\+" | cut -d'#' -f2`; do
    curl -X POST -d "body=refenced in ${COMMIT_HASH_MSG}" \
        ${GITLAB_URL}api/v3/projects/${PROJECT}/issues/${issue_id}/notes/?private_token=${PRIVATE_TOKEN}
done

Dont forget to make it executable with

chmod +x .git/hooks/post-commit

Moral of the story backtick placement is important