Git post-checkout hook that automatically updates your bundled gems (if applicable), re-generates your tags index using exuberant ctags, and tries to advise you about pending migrations.

post-checkout.sh

#!/bin/sh

set -e

OLDREV=$1
NEWREV=$2
IS_BRANCH_CHECKOUT=$3

function has_changes_to() {
  git diff --name-only "$OLDREV" "$NEWREV" -- "$1" | grep "$1" > /dev/null
}

if [ -e Gemfile ]; then
  echo '--> Checking Gem dependencies'
  has_changes_to Gemfile || bundle check > /dev/null || (
    echo '    Running bundle install'
    bundle install | grep 'Installing '
  )
fi

echo '--> Updating tags'
if [ -e Gemfile ]; then
  echo '    Generating tags from bundled Gems'
  bundle show --paths | xargs ctags -R 2>/dev/null
  echo '    Generating project tags'
fi
/usr/local/bin/ctags -a --extra=+f --exclude=.git --exclude=log --exclude=tmp -R * 2>/dev/null

if [ -e db/schema.rb ]; then
  echo '--> Checking for schema changes'
  has_changes_to db/migrate || echo '    You have pending migrations. Run `rake db:migrate` to update your database.'
fi