Clarifies configuration in zipkin sample

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-zipkin/src/main/java/sample/SampleZipkinApplication.java

@@ -36,8 +36,9 @@ import org.springframework.scheduling.annotation.EnableAsync;
 @Slf4j
 public class SampleZipkinApplication {
 
-	public static final String CLIENT_NAME = "testApp";
-
+	/**
+	 * Sleuth will not report trace data unless you define a sampler like below.
+	 */
 	@Bean
 	public Sampler defaultSampler() {
 		return new AlwaysSampler();

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-zipkin/src/main/resources/application.yml

@@ -3,8 +3,13 @@ server:
 
 spring:
   application:
-    name: testSleuthZipkin
+    # This ends up as the service name in zipkin
+    name: my-boot
+  zipkin:
+    # Uncomment to send to zipkin, replacing 192.168.99.100 with your docker-machine's IP address
+    # baseUrl: http://192.168.99.100:9411/
 
 sample:
   zipkin:
-    enabled: false
+    # When enabled=false, traces log to the console. Comment to send to zipkin
+    enabled: false