Support join datatype

[m0sviatoslav]

As far as I understood bundle doesn't support join datatype unlike ruflin/Elastica. Do you have join datatype in your roadmap?

{
  "mappings": {
    "_doc": {
      "properties": {
        "my_join_field": { 
          "type": "join",
          "relations": {
            "question": "answer" 
          }
        }
      }
    }
  }
}

[rhathas]

is there any plan on this?