code: function(connection, collection, attrName, attrDef, cb) {
        log.debug('addAttribute: ' + collection + ', attrName:', attrName);
        
        return connections[connection].addAttribute(collection, attrName, attrDef, cb);
      }
docs: AddAttribute
  
  Add a property to a class
  
  @param {String} connection
  @param {String} collection
  @param {String} attrName
  @param {Object} attrDef
  @param {Function} cb