canvas-lms/db/migrate/20130227205659_add_enrollment_last_activity_at.rb

class AddEnrollmentLastActivityAt < ActiveRecord::Migration
  tag :predeploy

  def self.up
    add_column :enrollments, :last_activity_at, :datetime
  end

  def self.down
    remove_column :enrollments, :last_activity_at
  end
end