make all email address in datamodel @example.com addresses

anonymize.rake

namespace :anonymize do
  desc "Replace all email addresses by an example.com variant."
  task :email => :environment do
    ActiveRecord::Base.connection.tables.map(&:singularize).map(&:camelize).map do |m|
      m.constantize rescue nil
    end.compact.select do |m|
      m.column_names.include?("email")
    end.each do |m|
      m.all.each do |v|
        v.update_attribute(:email, "#{v.email.sub('@', '-')}@example.com") unless v.email.blank? || v.email =~ /@example.com$/
      end
    end
  end
end