code: public DeploymentNode addDeploymentNode(String name, String description, String technology, int instances) {
          return addDeploymentNode(name, description, technology, instances, null);
      }
docs: Adds a child deployment node.
  
  @param name          the name of the deployment node
  @param description   a short description
  @param technology    the technology
  @param instances     the number of instances
  @return  a DeploymentNode object