Add documentation to examples

spring-rewrite-commons-examples/boot-3-upgrade-atomic/README.adoc

@@ -0,0 +1,3 @@
+= Atomic Upgrade to Boot 3
+
+This example shows how to implement a simple Boot application that uses `spring-rewrite-commons` to apply a recipe that upgrades a given Spring application (<3.1) to Spring Boot 3.1.

spring-rewrite-commons-examples/boot-3-upgrade-atomic/src/main/java/com/acme/example/SpringBoot3Upgrade.java

@@ -40,6 +40,8 @@
 @SpringBootApplication
 public class SpringBoot3Upgrade implements CommandLineRunner {
 
+	public static final String RECIPE_NAME = "org.openrewrite.java.spring.boot3.UpgradeSpringBoot_3_1";
+
 	public static void main(String[] args) {
 		SpringApplication.run(SpringBoot3Upgrade.class, args);
 	}
@@ -87,9 +89,8 @@ public void run(String... args) throws Exception {
 		ProjectResourceSet projectResourceSet = projectResourceSetFactory.create(baseDir, sourceFiles);
 
 		// discover
-		String recipeName = "org.openrewrite.java.spring.boot3.UpgradeSpringBoot_3_1";
 		List<Recipe> recipes = discovery.discoverRecipes();
-		Optional<Recipe> recipe = recipes.stream().filter(r -> recipeName.equals(r.getName())).findFirst();
+		Optional<Recipe> recipe = recipes.stream().filter(r -> RECIPE_NAME.equals(r.getName())).findFirst();
 
 		// apply
 		recipe.ifPresent((Recipe r) -> {

spring-rewrite-commons-examples/boot-3-upgrade-iterative/README.adoc

@@ -0,0 +1,4 @@
+= Iterative Upgrade to Boot 3 using PRs
+
+This example shows how to implement a simple Boot application that uses `spring-rewrite-commons` to apply recipes that upgrade the Spring Boot PetClinic from 2.3.x to Spring Boot 3.1 by applying recipes to upgrade from minor to minor version by creating PRs for every recipe run.
+No new recipes are applied until the last PR has been merged or closed.