Introduced service `popular`

[demos/kafka/wordcount] / counter

diff --git a/counter b/counter
index 58681eb..f9156ed 160000 (submodule)
--- a/counter
+++ b/counter
@@ -1 +1 @@
-Subproject commit 58681eb5c2ea655385c8209b07330e4ef0ab2c49
+Subproject commit f9156ed2e1f43b64d39cc39a13d12ca8c0d24219