code: public WarProbeOption overlay(String overlayPath) {
          overlays.add(new File(overlayPath).toURI().toString());
          return this;
      }
docs: Adds an overlay from the given path to the WAR. This is similar to the overlay concept of the
  Maven WAR Plugin. If the overlay path is a directory, its contents are copied recursively to
  the root of the WAR. If the overlay path is an archive, its exploded contents are copied to
  the root of the WAR. All overlays are copied in the given order. All overlay are copied
  before any libraries, classes or resources.
  
  @param overlayPath
  path to overlay
  @return {@code this} for fluent syntax