AutoIndexing does not work well with transactions

[Gasparila]

• Rails version: 5.1.6
• Algolia Rails integration version: 1.22

Description

@algolia_must_reindex is reset in every validate call. This means that a record
that is updated multiple times in a transaction will only be indexed if the
final update marks as must reindex

Steps To Reproduce

class AnyModel < ActiveRecord::Base
  include AlgoliaSearch
  
  algoliasearch do
    attribute(:name)
  end
end

# after_commit will have  @algolia_must_reindex = false
AnyModel.transaction do
  instance_of_model.update!(name: "foobar")
  instance_of_model.update!(unrelated_column: 23)
end

Suggested Fix

Change first line of def algolia_mark_must_reindex to

@algolia_must_reindex ||=

[julienbourdeau]

Fixed by #354