Adding functionality to every model in a system

auto_strip_text_attributes.rb

# This file is in lib

module AutoStripTextAttributes
  extend ActiveSupport::Concern

  included do
    text_columns = columns.collect do |c|
      c.name.to_sym if c.type == :string || c.type == :text
    end.compact

    auto_strip_attributes(*text_columns) unless text_columns.empty?
  end

end

model_tracker.rb

require 'auto_strip_text_attributes'

# This file is in config/initializers

module ActiveRecordModelTracker

  def inherited(by_our_model)
    by_our_model.__send__ :include, AutoStripTextAttributes
    super
  end

end

ActiveRecord::Base.send :include, ActiveRecordModelTracker unless $rails_rake_task

I use #include instead of #extend because I want to be able to call class methods from my mixin.