Expose clusters in R

[woodthom2]

Description

See also front end issue harmonydata/app#42

The API is now grouping items into topics.
Please can we expose this functionality from the R library.

You can see this in the call to /text/match, e.g.:

curl -X 'POST' \
  'http://localhost:8000/text/match?include_catalogue_matches=false&is_negate=true' \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
  "instruments": [
    {
      
      "questions": [
        {
          "question_text": "Feeling nervous, anxious, or on edge"
        },
        {
          "question_text": "Not being able to stop or control worrying"
        }
      ]
    },
    {
      "questions": [
        {
          "question_text": "Sentir-se nervoso/a, ansioso/a ou muito tenso/a"
        },
        {
          "question_text": " Não ser capaz de impedir ou de controlar as preocupações"
        }
      ]
    }
  ]
}'

{
  "instruments": [
  
///... ///
    }
  ],
  "clusters": [
    {
      "cluster_id": 0,
      "centroid_id": 0,
      "item_ids": [
        0,
        2
      ],
      "text_description": "Feeling nervous, anxious, or on edge"
    },
    {
      "cluster_id": 1,
      "centroid_id": 1,
      "item_ids": [
        1,
        3
      ],
      "text_description": "Not being able to stop or control worrying"
    }
  ]
}

Rationale

Many users have requested this feature.