Add Leadership Election example and configuration

spring-cloud/spring-cloud-consul/src/main/java/com/baeldung/spring/cloud/consul/leadership/LeadershipElection.java

@@ -0,0 +1,16 @@
+package com.baeldung.spring.cloud.consul.leadership;
+
+import java.util.concurrent.ExecutionException;
+
+import net.kinguin.leadership.consul.factory.SimpleConsulClusterFactory;
+
+public class LeadershipElection {
+    public static void main(String[] args) throws ExecutionException, InterruptedException {
+        new SimpleConsulClusterFactory()
+            .mode(SimpleConsulClusterFactory.MODE_MULTI)
+            .debug(true)
+            .build()
+            .asObservable()
+            .subscribe(i -> System.out.println(i));
+    }
+}

spring-cloud/spring-cloud-consul/src/main/resources/application.yml

@@ -11,4 +11,19 @@ spring:
         enabled: true
         instanceId: ${spring.application.name}:${random.value}
 server:
-  port: 0
+  port: 0
+
+cluster:
+  leader:
+    serviceName: cluster
+    serviceId: node-1
+    consul:
+      host: localhost
+      port: 8500
+      discovery:
+        enabled: false
+    session:
+      ttl: 15
+      refresh: 7
+    election:
+      envelopeTemplate: services/%s/leader