How to create an index that has NULLS LAST in Rails?

Question

I read https://apidock.com/rails/ActiveRecord/ConnectionAdapters/SchemaStatements/add_index and http://guides.rubyonrails.org/active_record_migrations.html.

I don't see how to create an index like:

CREATE INDEX ON users (id DESC NULLS LAST);

Did not see docs on how to create and index with NULLS LAST.

Rails 4.2.10

PostgreSQL

Answer 1

Active Record now supports NULLS LAST in an index with the order argument:

add_index(
    :my_table,
    [:my_column],
    order: { my_column: "DESC NULLS LAST" }
)