ElastiSearch fields mapping customisation

Changing the field mapping ElasticSearch is using

With ElasticSearch, you don't need to explicitly define everything (field names, field types, indices, ...). He will try to do it automatically.
When uploading data using the REST api to an index which is not yet created, a new one with the name provided will be created. Default mapping (the types to use for each fields) and settings will be applied.