rename the file name

[georgehao]

time="2018-12-19T14:22:20Z" level=error msg="_bulk failed list [156]" error="&elastic.ErrorDetails{Type:"illegal_argument_exception", Reason:"[name] is defined as an object in mapping [categories] but this name is already used for a field in other types", ResourceType:"", ResourceId:"", Index:"", Phase:"", Grouped:false, CausedBy:map[string]interface {}(nil), RootCause:[]*elastic.ErrorDetails(nil), FailedShards:[]map[string]interface {}(nil)}" executionID=2 id=5bfbc7cdd6d62d4c9b2d88ef index=story type=categories version=5 writer=elasticsearch

Adapter

Source: mongodb Sink: ElasticSearch 5.x

Question

I want to rename the name of categories, How to do it ?

I see the rename function, but the field_map means what ?