Rails: Prefer timestamps over booleans (#723)

Back boolean concepts like deleted? or published? with timestamps columns in the
database `deleted_at`, `published_at`.

This can be valuable when you need to know **when** something took place.

[1]: https://github.com/calebhearth/time_for_a_boolean

Author: stevepolitodesign

rails/README.md

@@ -3,6 +3,8 @@
 - Use private instead of protected when defining controller methods.
 - Name date columns with `_on` suffixes.
 - Name datetime columns with `_at` suffixes.
+- Back boolean concepts like deleted? or published? with timestamps columns in the database `deleted_at`, `published_at`.
+  This can be valuable when you need to know **when** something took place. [Time for A Boolean](https://github.com/calebhearth/time_for_a_boolean) provides a nice interface for this.
 - Name time columns (referring to a time of day with no date) with `_time`
   suffixes.
 - Name initializers for their gem name.