support enum

[pekopekopekopayo]

Fixes #1555
Related: #1644

Problem

When searching enum attributes by key (e.g., temperament_eq: 'choleric'), Ransack identified the column type as :integer and cast the value via String#to_i, resulting in 'choleric'.to_i == 0. This produced incorrect queries like WHERE temperament = 0 instead of WHERE temperament = 2.

Solution

In Rails, Person.where(temperament: 'choleric') and Person.where(temperament: 2) both produce the same query — ActiveRecord handles the mapping internally. Ransack should behave the same way. To achieve this, Attribute#type now returns :enum for enum attributes, and Value#cast(:enum) passes the raw value through to ActiveRecord instead of attempting its own conversion.

A regression test for #1644 has also been included to ensure boolean predicate casting remains unaffected.

Changes

• Attribute#type — returns :enum when the attribute is a defined enum
• Value#cast(:enum) — returns raw value, delegating conversion to ActiveRecord
• Added enum search specs (key and integer value)
• Added regression test for Non-boolean values passed to boolean predicates are no longer cast #1644 (boolean predicate casting)

[pekopekopekopayo]

While enum is not technically a database type, it is treated as one here exceptionally to prevent Ransack from incorrectly casting the value as an integer.

[pekopekopekopayo]

@deivid-rodriguez
@scarroll32

Could you please review this?