add "initial" anchor

fixes "initial" link in how_to_complete_this_guide.adoc

README.adoc

@@ -26,6 +26,7 @@ include::https://raw.githubusercontent.com/spring-guides/getting-started-macros/
 
 include::https://raw.githubusercontent.com/spring-guides/getting-started-macros/master/hide-show-sts.adoc[]
 
+[[initial]]
 == Learn what you can do with Spring Boot
 
 Spring Boot offers a fast way to build applications. It looks at your classpath and at beans you have configured, makes reasonable assumptions about what you're missing, and adds it. With Spring Boot you can focus more on business features and less on infrastructure.