fix: support of Ctrl-C

Before, bash would not correctly handle the subprocess, and would fail
to kill itself.

Signed-off-by: Valentin Lab <valentin.lab@kalysto.org>

Dockerfile

@@ -118,4 +118,8 @@ RUN apk add openssh-client
 ## install compose
 COPY ./bin/ /usr/local/bin/
 
-ENTRYPOINT ["/usr/local/bin/compose-core"]
+## Fixes Ctrl-C handling:
+##   see https://github.com/moby/moby/issues/2838#issuecomment-402491110
+RUN apk add --no-cache tini
+# Tini is now available at /sbin/tini
+ENTRYPOINT ["/sbin/tini", "--", "/usr/local/bin/compose-core"]