rClient = retrieve.createSolrClient({
  cluster_id: 'INSERT YOUR CLUSTER ID HERE',
  collection_name: 'example_collection'
});

// add a document
var doc = { id : 1234, title_t : 'Hello', text_field_s: 'some text' };
solrClient.add(doc, function(err) {
  if(err) {
    console.log('Error indexing document: ' + err);
  } else {
    console.log('Indexed a document.');
    solrClient.commit(function(err) {
      if(err) {
        console.log('Error committing change: ' + err);
      } else {
        console.log