Rails 4.1 introduced a new file for storing such type of information at config/secrets.yml
. I would suggest using this one if you are on, or planning to upgrade to, Rails 4.1 (in the spirit of convention over configuration).
You can retrieve these within Rails as such:
Rails.application.secrets.bank_account.number
and so on. Make sure to tell your VCS to ignore this file. You can find more information regarding secrets.yml in the official release notes.