Add a Spring Boot example and integration code.

Change-Id: Ia11dea607c74d9b4cc9a698e9ec92e930bd03f37
diff --git a/examples/spring-boot/src/main/java/eu/mulk/quarkus/googlecloud/jsonlogging/example/RootResource.java b/examples/spring-boot/src/main/java/eu/mulk/quarkus/googlecloud/jsonlogging/example/RootResource.java
new file mode 100644
index 0000000..b3197fd
--- /dev/null
+++ b/examples/spring-boot/src/main/java/eu/mulk/quarkus/googlecloud/jsonlogging/example/RootResource.java
@@ -0,0 +1,33 @@
+package eu.mulk.quarkus.googlecloud.jsonlogging.example;
+
+import eu.mulk.quarkus.googlecloud.jsonlogging.KeyValueParameter;
+import eu.mulk.quarkus.googlecloud.jsonlogging.Label;
+import javax.annotation.PostConstruct;
+import org.jboss.logging.Logger;
+import org.jboss.logging.MDC;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController("/")
+public class RootResource {
+
+  static final Logger log = Logger.getLogger(RootResource.class);
+
+  @PostConstruct
+  public void init() {
+    log.warn("Hey!");
+  }
+
+  @GetMapping(produces = "text/plain")
+  public String hello() {
+    MDC.put("requestMethod", "GET");
+    log.infof(
+        "Hello %s.",
+        "Mulkiatsch",
+        KeyValueParameter.of("a", "b"),
+        Label.of("app", "foo"),
+        KeyValueParameter.of("version", 10));
+    throw new IllegalStateException();
+    // return "ok";
+  }
+}