i18n documentation for required belongs_to message

When you don't explicitly provide `optional: true` to a `belongs_to`
definition, rails adds a validation to ensure presence of the
`belongs_to` validation.

However, when the validation is added, it is added with a message key of
`:required`, which was not documented in the "Translations for Active
Record Models" section of the i18n guides.

Here are the lines that add the `:required` message:
https://github.com/rails/rails/blob/c3e3577f9d5058382504773bf0d32afa15cb131e/activerecord/lib/active_record/associations/builder/belongs_to.rb#L136-L138

This commit adds the "non-optional association" validation to the table,
so rails users know how to override the message for this validation. The
default message is "must exist".

0 files changed, 0 insertions, 0 deletions