method_missing

speciality.rb

class Speciality < ActiveRecord::Base
  validates :code, presence: true

  private
    def method_missing(method, *args, &block)
      if method.to_s =~ /^(.+)[?]$/
        run_code_comparation_method($1, *args, &block)
      else
        super
      end
    end

    def run_code_comparation_method(attrs, *args, &block)
      attributes['code'] == attrs
    end
end