Rails 3.2 LTS error: uninitialized constant Airbrake::Rails::ActiveRecord::Base

[masonhale]

When using the Rails LTS fork of Rails 3.2 (see https://railslts.com), after upgrading airbrake from 11.0.1 to 13.0.3, trying to initialize the app to start the server or run any rake tasks, results in the following error:

/gems/airbrake-13.0.3/lib/airbrake/rails/railties/active_record_tie.rb:33:in `tie_activerecord_callback_fix': uninitialized constant Airbrake::Rails::ActiveRecord::Base (NameError)