code: function(config, value) {
          if (value === undefined || value === null) {
              return false;
          }
          
          var length = value.length,
              min    = config.min,
              max    = config.max;
          
          if ((min && length < min) || (max && length > max)) {
              return false;
          } else {
              return true;
          }
      }
docs: Returns true if the given value is between the configured min and max values.
  For example:
  
  validations: [{type: 'length', field: 'name', min: 2}]
  
  @param {Object} config Config object
  @param {String} value The value to validate
  @return {Boolean} True if the value passes validation