Used in conjunction with [this script](https://gist.github.com/searls/5c6b77213dbc7202ca39f4e70d975eee) to make it easier to git bisect rails apps whose database changes during the affected sha range

rails_bisect_step

#!/usr/bin/env bash

# Usage:
#
#   First, be sure you're running `git bisect start --no-checkout`, so you can
#   checkout the bisect head yourself and do some pre-flight stuff like rewind
#   migrations
#
#   $ git bisect good
#   Bisecting: 22 revisions left to test after this (roughly 5 steps)
#   [8d85ccd2ce0fdbe3a1c3408f667b1cf15759c162] UI and validation tweaks
#
#   $ rails_bisect_step

# pre-checkout
bin/rake db:migrate VERSION="$(migration_version_at_ref BISECT_HEAD)" 2>/dev/null || echo "No such migration"
git reset --hard

git checkout BISECT_HEAD

# post-checkout:
bin/rake db:migrate