update: reduce a docker layer

Dockerfile

@@ -4,9 +4,9 @@ RUN apk --update add --no-cache curl wget && \
     sh /asset.sh
 
 FROM alpine
-COPY ./init.sh /
-COPY ./overture /etc/overture/
+COPY ["./overture/", "./init.sh", "/etc/overture/"]
 COPY --from=asset /tmp/asset/ /usr/bin/
-RUN mkdir -p /etc/cleardns && \
-    sed -i '$i\0\t2\t*\t*\t*\t/etc/overture/update.sh' /var/spool/cron/crontabs/root
+RUN mv /etc/overture/init.sh / && \
+    mkdir -p /etc/cleardns && \
+    sed -i '$i\0\t4\t*\t*\t*\t/etc/overture/update.sh' /var/spool/cron/crontabs/root
 CMD ["sh","/init.sh"]