Zero Downtime - Remove a column

zero_downtime_remove_column.rb

class User < ActiveRecord::Base
...
  # << REMOVE ON NEXT RELASE  
  def self.columns
    super.reject { |c| c.name == "removed_column" }
  end
  # >> REMOVE ON NEXT RELEASE
...
end

Hi. I am using same code and want to remove email from user. But if I do User.first.email it exist. Even User.first.attributes["email"] exist.