Add ActiveRecord::Relation#in_batches

`in_batches` yields Relation objects if a block is given, otherwise it
returns an instance of `BatchEnumerator`. The existing `find_each` and
`find_in_batches` methods work with batches of records. The new API
allows working with relation batches as well.

Examples:

    Person.in_batches.each_record(&:party_all_night!)
    Person.in_batches.update_all(awesome: true)
    Person.in_batches.delete_all
    Person.in_batches.map do |relation|
      relation.delete_all
      sleep 10 # Throttles the delete queries
    end

0 files changed, 0 insertions, 0 deletions