def validates_numericalness_of(*attribute_names)
      options = Macros.extract_options(attribute_names)
      validation_rules.add(Rule::Value,         attribute_names, options)
      validation_rules.add(Rule::Numericalness, attribute_names, options)
    end
def validates_numericalness_of(*attribute_names)
      options = Macros.extract_options(attribute_names)
      validation_rules.add(Rule::Value,         attribute_names, options)
      validation_rules.add(Rule::Numericalness, attribute_names, options)
    end
Validate whether a field is numeric.

 @option [Boolean] :allow_nil
   true if number can be nil, false if not.

 @option [Boolean] :allow_blank
   true if number can be blank, false if not.

 @option [String] :message
   Custom error message, also can be a callable object that takes
   an object (for pure Ruby objects) or object and property
   (for DM resources).

 @option [Numeric] :precision
   Required precision of a value.

 @option [Numeric] :scale
   Required scale of a value.

 @option [Numeric] :gte
   'Greater than or equal to' requirement.

 @option [Numeric] :lte
   'Less than or equal to' requirement.

 @option [Numeric] :lt
   'Less than' requirement.

 @option [Numeric] :gt
   'Greater than' requirement.

 @option [Numeric] :eq
   'Equal' requirement.

 @option [Numeric] :ne
   'Not equal' requirement.

 @option [Boolean] :integer_only
   Use to restrict allowed values to integers.