tableless_columns.rb

class User < ActiveRecord::Base
  include TablelessColumns

  tableless_column :license_accepted, :boolean

  # other fields that are corresponding to table columns
end

module TablelessColumns
  def self.included(base)
    base.extend(ClassMethods)
  end

  module ClassMethods
    def tableless_columns
      read_inheritable_attribute(:tableless_columns)
    end

    def tableless_column(name, sql_type = nil, default = nil, null = true)
      write_inheritable_attribute(:tableless_columns, {}) if tableless_columns.nil?
      tableless_columns[name] = ActiveRecord::ConnectionAdapters::Column.new(name.to_s, default, sql_type.to_s, null)

      define_method("#{name.to_s}=".to_sym) { |value| instance_variable_set(to_variable(name), value) }
      define_method(name) { self.class.tableless_columns[name].type_cast(instance_variable_get(to_variable(name))) }
    end
  end

  def to_variable(sym)
    "@#{sym.to_s}".to_sym
  end
end