radar/paranoia — pull request #140 by smdern (2014-06-24 18:57:37+00:00)
Title: Add optional sentinel_value

MySQL ignores null columns when it comes to resolving unique index constraints. This means that all of our unique constraints that involve nullable columns are problematic. This will allow the `deleted_at` value to be set globally or per model.

`acts_as_paranoid sentinel_value: 0`

or globally in a rails initializer
`Paranoia.default_sentinel_value = 0`