How to automatically prepend git commit with a branch name. TLDR, from the root of each repository you want to use this, install using `curl -L https://goo.gl/5Mmuoi -o .git/hooks/prepare-commit-msg --create-dirs; chmod 744 .git/hooks/prepare-commit-msg`

prepare-commit-msg.sh

#!/bin/bash

# To update or install in a new repository, run the following command
# N=.git/hooks/prepare-commit-msg ; curl -L https://goo.gl/5Mmuoi -o $N --create-dirs; chmod 744 $N

# Assuming all branches are created as `WWW-nnn-Human-readable-suffixes`
# this commit-msg hook will prepend all commit messages with the ticket
# name/number, for example:
# Branch: ADV-007-License-to-kill
# Message: Bad guy has been identified.
# Prepends: ADV-007:
# Result: ADV-007: Bad guy has been identified.

# This way you can customize which branches should be skipped when
# prepending commit message. (Untested after implementing trimming)
if [ -z "$BRANCHES_TO_SKIP" ]; then
  BRANCHES_TO_SKIP=(master develop test)
fi

# Get the full branch name
BRANCH_NAME=$(git symbolic-ref --short HEAD)
# Chop of sub-dirs (like `feature/`)
BRANCH_NAME="${BRANCH_NAME##*/}"
# Keep only ticket-number, ditch the human readable part i.e. `ADV-000`
BRANCH_NAME=$(echo $BRANCH_NAME | sed -e 's:^\([^-]*-[^-]*\)-.*:\1:' -e \
    'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/')

BRANCH_EXCLUDED=$(printf "%s\n" "${BRANCHES_TO_SKIP[@]}" | grep -c "^$BRANCH_NAME$")
BRANCH_IN_COMMIT=$(grep -c "\[$BRANCH_NAME\]" $1)

if [ -n "$BRANCH_NAME" ] && ! [[ $BRANCH_EXCLUDED -eq 1 ]] && ! [[ $BRANCH_IN_COMMIT -ge 1 ]]; then
  sed -i.bak -e "1s/^/$BRANCH_NAME: /" $1
fi

Forked so I can adapts this concept for Bestseller.com
To implement, rename .git/hooks/prepare-commit-msg.sample to prepare-commit-msg, paste the script and make the file executable.

HOWTO install this file.

1. Go to the directory of the repository you want to enable this on
2. In that repository go to the directory .git/hooks (create it if it doesn't exist)
3. Copy this gist into the directory
4. Rename to prepare-commit-msg (notice, no extension)
5. Make sure prepare-commit-msg is executable, if not, make it so (chmod +x prepare-commit-msg)

Quick Install:

1. Goto your git root directory
2. Run curl -L https://goo.gl/5Mmuoi -o .git/hooks/prepare-commit-msg --create-dirs; chmod 744 .git/hooks/prepare-commit-msg

Prep so that every repository on your machine gets this:

1. git config --global init.templatedir '~/.git_template'
2. N=~/.git_template/hooks/prepare-commit-msg ; curl -L https://goo.gl/5Mmuoi -o $N --create-dirs; chmod 744 $N
3. For existing repositories run git init from the root of it, for new repositories, git clone will simply add the hook.

I understand you can also install it as a global hook that 'just works' for all repositories, but by the above setup you can also easily disable it for a couple of repositories by simply removing the hook after clone/init.