code: function(config, value) {
          return config.list && Ext.Array.indexOf(config.list,value) != -1;
      }
docs: Validates that the given value is present in the configured `list`.
  For example:
  
  validations: [{type: 'inclusion', field: 'gender', list: ['Male', 'Female']}]
  
  @param {Object} config Config object
  @param {String} value The value to validate
  @return {Boolean} True if the value is present in the list