Use TestContainers for Gretty integration tests

samples/javaconfig/redis/src/main/java/sample/Config.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2016 the original author or authors.
+ * Copyright 2014-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,9 +17,11 @@
 package sample;
 
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Import;
 import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
 import org.springframework.session.data.redis.config.annotation.web.http.EnableRedisHttpSession;
 
+@Import(EmbeddedRedisConfig.class)
 // tag::class[]
 @EnableRedisHttpSession // <1>
 public class Config {