code: function (businessRule) {
      if (!businessRule || !_.isObject(businessRule)) {
        var err = new Error('Please inject a valid businessRule object!');
        debug(err);
        throw err;
      }
  
      if (this.businessRules.indexOf(businessRule) < 0) {
        businessRule.defineAggregate(this);
        this.businessRules.push(businessRule);
        this.businessRules = _.sortBy(this.businessRules, function(br) {
          return br.priority;
        });
      }
    }
docs: Add businessRule module.
  @param {BusinessRule} businessRule The businessRule module to be injected.