Bad JSON for array atomic updates

[serggl]

When I try document.add_field(indexed_name, ['value1', 'value2'],{update: :set}) rsolr will build JSON in a wrong manner, so Solr returns Error parsing JSON field value. Unexpected OBJECT_START

Here is a sample JSON, which is being produced for the sample above

{
  "id": "Post 917", 
  "type": ["Post"], 
  "tag_list_sms": [
    {"set": "value 1"}, 
    {"set": "value 2"}
  ]
}

An error will be

     RSolr::Error::Http:
       RSolr::Error::Http - 400 Bad Request
       Error: {"responseHeader":{"status":400,"QTime":3},"error":{"msg":"Error parsing JSON field value. Unexpected OBJECT_START at [77], field=tag_list_sms","code":400}}
     
       URI: http://localhost:8983/solr/default/update?wt=json
       Request Headers: {"Content-Type"=>"application/json"}

I believe a proper format should be:

  "tag_list_sms": {
      "set": ["value 1", "value 2"]
    }