Add named anchors to boot reference

docs/src/docs/asciidoc/guides/boot.adoc

@@ -91,6 +91,7 @@ spring.redis.port=6379
 
 For more information, refer to http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-connecting-to-redis[Connecting to Redis] portion of the Spring Boot documentation.
 
+[[boot-servlet-configuration]]
 == Servlet Container Initialization
 
 Our <<boot-spring-configuration,Spring Configuration>> created a Spring Bean named `springSessionRepositoryFilter` that implements `Filter`.
@@ -105,6 +106,7 @@ Fortunately, Spring Boot takes care of both of these steps for us.
 
 The boot Sample Application demonstrates how to use Spring Session to transparently leverage Redis to back a web application's `HttpSession` when using Spring Boot.
 
+[[boot-running]]
 === Running the boot Sample Application
 
 You can run the sample by obtaining the {download-url}[source code] and invoking the following command:
@@ -113,6 +115,7 @@ You can run the sample by obtaining the {download-url}[source code] and invoking
 
 You should now be able to access the application at http://localhost:8080/
 
+[[boot-explore]]
 === Exploring the security Sample Application
 
 Try using the application. Enter the following to log in:
@@ -124,6 +127,7 @@ Now click the **Login** button.
 You should now see a message indicating your are logged in with the user entered previously.
 The user's information is stored in Redis rather than Tomcat's `HttpSession` implementation.
 
+[[boot-how]]
 === How does it work?
 
 Instead of using Tomcat's `HttpSession`, we are actually persisting the values in Redis.