Simple module for dynamic values

mod_machine.rb

module ModMachine
  extend ActiveSupport::Concern

  included do
  end
 
  module ClassMethods
    # 
    # Builds a module with constants assigned to the index passed in the `options` array. Be sure
    # to pass all arguments as you would write them manually. In other words `attribute` and any 
    # constants passed in `options` should be classified case (e.g. ThisModule).
    #
    # `attribute` = Name of the class attribute that should be the module's name. MUST be a attribute
    #               of the class.
    # `options`   = Array of constants identified with `attribute`
    #
    # example
    #     mod_machine_for("Category", ["PeerReviewed", "NonPeerReviewed", "CaseStudy"])
    #
    def mod_machine_for(attribute, options=[])
      constants = ""
      options.each_with_index do |constant, index|
        constants << "#{constant} = #{index}; "
      end
      mod = %Q{module #{attribute}; #{constants} end}
      self.module_eval(mod)
      build_boolean_instance_methods(attribute, options)
      build_mutable_instance_methods(attribute, options)
    end
 
    #
    # Builds out the boolean methods for constants defined in `mod_machine_for`.
    # Arguments must follow the same format as the aforementioned method.
    #
    def build_boolean_instance_methods(attribute, options=[])
      options.each do |const|
        class_eval <<-RUBY
          def #{const.to_s.demodulize.tableize.singularize}?
            self.#{attribute.downcase} == #{attribute}::#{const.to_s.demodulize}
          end
        RUBY
      end
    end
    
    #
    # Builds out mutable update methods for constants defined in `mod_machine_for`.
    # Arguments must follow the same format as the aforementioned method.
    #
    # example
    #   object.case_study!
    #     #=> UPDATE 'objects' SET 'category' = 2 WHERE 'objects'.'id' = 1;
    #   object.case_study?
    #     #=> true
    #
    def build_mutable_instance_methods(attribute, options=[])
      column = ":" + attribute.to_s.downcase
      options.each do |const|
        class_eval <<-RUBY
          def #{const.to_s.demodulize.tableize.singularize}!
            update_attribute #{column}, #{attribute}::#{const.to_s.demodulize}
          end
        RUBY
      end
    end
  end #End ClassMethods
end #End StateMachine

Example:

mod_machine_for("Status", ["Active", "Inactive", "Archived"])

builds out methods for active?, inactive?, archived?, etc.
builds out methods for active!, inactive!, archived!, etc.

Would greatly appreciate feedback on ways to make this more concise, and generally better.

In Rails 4.1 you should just use ActiveRecord::Enum as it is the same functionality. http://api.rubyonrails.org/v4.1.0/classes/ActiveRecord/Enum.html