code: public BoxTaskAssignment.Info addAssignment(BoxUser assignTo) {
          JsonObject taskJSON = new JsonObject();
          taskJSON.add("type", "task");
          taskJSON.add("id", this.getID());
  
          JsonObject assignToJSON = new JsonObject();
          assignToJSON.add("id", assignTo.getID());
  
          JsonObject requestJSON = new JsonObject();
          requestJSON.add("task", taskJSON);
          requestJSON.add("assign_to", assignToJSON);
  
          URL url = ADD_TASK_ASSIGNMENT_URL_TEMPLATE.build(this.getAPI().getBaseURL());
          BoxJSONRequest request = new BoxJSONRequest(this.getAPI(), url, "POST");
          request.setBody(requestJSON.toString());
          BoxJSONResponse response = (BoxJSONResponse) request.send();
          JsonObject responseJSON = JsonObject.readFrom(response.getJSON());
  
          BoxTaskAssignment addedAssignment = new BoxTaskAssignment(this.getAPI(), responseJSON.get("id").asString());
          return addedAssignment.new Info(responseJSON);
      }
docs: Adds a new assignment to this task.
  @param assignTo the user to assign the assignment to.
  @return information about the newly added task assignment.