code: function() {
      var attrs = this.changedAttributes();
      var relationKeys = this.relationDefinitions ? Object.keys(this.relationDefinitions) : [];
      attrs = _.omit(attrs, relationKeys);
      return attrs;
    }
docs: ## BaseModel.prototype.changedAttributesWithoutRelations
  
  omits relations from changedAttributes
  @returns {Object} object containing changed attributes