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