code: public JSONObject addObject(JSONObject obj, String objectID) throws AlgoliaException {
      return this.addObject(obj, objectID, RequestOptions.empty);
    }
docs: Add an object in this index with a uniq identifier
  
  @param obj      the object to add
  @param objectID the objectID associated to this object
  (if this objectID already exist the old object will be overriden)