git tag a release with commit messages

tag_release.sh

#!/bin/bash

# Check out production branch and bring it up to date.
git fetch origin
git checkout production
git reset --hard origin/production

# Create a name for the new tag.
NEW_TAG=$(date +"%Y%m%d-%H%M")

# Grab the last tag.
LAST_TAG=$(git tag | xargs -I@ git log --format=format:"%ai @%n" -1 @ | sort | awk '{print $4}' | tail -n1)

# Tag the release and push it to github.
git tag -a ${NEW_TAG} -m "$(git log --pretty=oneline --no-merges ${LAST_TAG}..${NEW_TAG})"
git push origin ${NEW_TAG}