upgrade heroku postgres from crane to yanari

upgrade_postgres.bash

# this can be done anytime
heroku addons:add heroku-postgresql:standard-yanari --app nav-chronos; heroku pg:wait
# about 3m30s

heroku maintenance:on
heroku ps:scale worker=0

heroku pgbackups:capture --expire
# less than 20 min

heroku pgbackups:restore HEROKU_POSTGRESQL_PINK
# less than 20 min

heroku pg:promote HEROKU_POSTGRESQL_PINK

heroku maintenance:off
heroku ps:scale worker=1

# destroy old database once your sure the new database is working