docker images: clean kill using tini

- PID 1 does not have default signal handlers which causes
unclean shutdown of processes
Signed-off-by: Lakshya Singh <lakshay.singh1108@gmail.com>

txood/Dockerfile

@@ -32,7 +32,8 @@ RUN apk update && \
       libev-dev \
       curl-dev \
       curl \
-      jq
+      jq \
+      tini
 
 COPY --from=builder /usr/local/bin/txood /usr/bin/txood
 
@@ -47,5 +48,5 @@ VOLUME ["${TXOO_DATA}"]
 HEALTHCHECK --interval=5s --timeout=10s --start-period=5s \
     CMD ["/healthcheck.sh"]
 
-ENTRYPOINT ["/entrypoint.sh"]
+ENTRYPOINT ["/sbin/tini", "--", "/entrypoint.sh"]
 CMD ["txood"]