Fix CMD command in Dockerfile for compatibility with Compose

The previous form worked fine with Kubernetes but doesn’t seem to be
compatible with docker-compose.

Fixes #64

ops/Dockerfile

@@ -26,4 +26,4 @@ RUN mkdir -p ${HOME} && \
     adduser -s /bin/sh -u 1001 -G root -h ${HOME} -S -D default && \
     chown -R 1001:0 ${HOME}
 ENTRYPOINT ["/opt/app/bin/keila"]
-CMD "start"
+CMD ["start"]

ops/docker-compose.yml

@@ -8,7 +8,8 @@ services:
     depends_on:
       - postgres
     build:
-      context: .
+      context: ../
+      dockerfile: ops/Dockerfile
     environment:
       SECRET_KEY_BASE: "${YOUR_SECRET_KEY}"
       DB_URL: "postgres://postgres:postgres@postgres/postgres"