enabling dumb-init for shovel

Change-Id: I6bb546c21866f4b6d8f1095079f288945080396d
diff --git a/docker/Dockerfile.shovel b/docker/Dockerfile.shovel
index 4ae1808..7270e20 100644
--- a/docker/Dockerfile.shovel
+++ b/docker/Dockerfile.shovel
@@ -27,5 +27,7 @@
 COPY common /shovel/common
 COPY shovel /shovel/shovel
 
+ENTRYPOINT ["/usr/bin/dumb-init", "--"]
+
 # Exposing process and default entry point
 CMD ["python", "shovel/shovel/main.py"]