Update README to use ld-relay

Author: arun251

README.md

@@ -65,7 +65,7 @@ Using Redis
 
 2. Create the LDClient with the Redis feature requester as an option:
 
-    $client = new LaunchDarkly\LDClient("your_sdk_key", ['feature_requester_class' => 'LaunchDarkly\LDDFeatureRequester']);
+    $client = new LaunchDarkly\LDClient("your_sdk_key", ['feature_requester_class' => 'LaunchDarkly\LDDFeatureRequester', 'redis_host' => 'your.redis.host', 'redis_port' => 6379]);
 
 Testing
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