scinote-web/db/migrate/20160513143117_refresh_assigned_samples_counters.rb

class RefreshAssignedSamplesCounters < ActiveRecord::Migration[4.2]
  def up
    # Reset the counters for assigned samples
    Sample.find_each do |sample|
      sample.update(nr_of_modules_assigned_to: sample.my_modules.count)
    end

    MyModule.find_each do |my_module|
      my_module.update(nr_of_assigned_samples: my_module.samples.count)
    end
  end
end