text: 'use strict';
  
  module.exports = function(stringToContain) {
      this.pushValidation({
          name: 'contains',
          validator: function(value) {
              return validator(value, stringToContain);
          }
      });
      return this;
  };
  
  function validator(value, stringToContain) {
      return typeof value === 'string' && value.indexOf(stringToContain) !== -1;
  }