add swagger to spring boot application code example

Example: spring boot example with swagger

@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
    registry.addResourceHandler("swagger-ui.html")
      .addResourceLocations("classpath:/META-INF/resources/");

    registry.addResourceHandler("/webjars/**")
      .addResourceLocations("classpath:/META-INF/resources/webjars/");
}