code: function JoinColumn(joinColumnConfiguration) {
      return function (targetObject, propertyKey) {
          var entityMetadata = targetObject;
          if (!entityMetadata.joinColumnMap) {
              entityMetadata.joinColumnMap = {};
          }
          entityMetadata.joinColumnMap[propertyKey] = joinColumnConfiguration;
      };
  }
docs: Annotates columns.
  
  @param columnConfiguration
  @returns {function(Function)}
  @constructor