/var/cache/apt may not exist

Dockerfile

@@ -4,7 +4,7 @@ MAINTAINER Girish Ramakrishnan <girish@cloudron.io>
 # this can be removed in next base image update
 RUN apt-get update && \
     apt-get install -y php7.0-zip crudini && \
-    rm -r /var/cache/apt /var/lib/apt/lists
+    rm -rf /var/cache/apt /var/lib/apt/lists
 
 RUN mkdir -p /app/code
 WORKDIR /app/code