Merge pull request #560 from BruceWangNo1/master

some minor fixes to docker/Dockerfile

docker/Dockerfile

@@ -1,9 +1,10 @@
 FROM frolvlad/alpine-glibc:alpine-3.5
 
-RUN apk add --no-cache --virtual=build-dependencies --update curl wget ca-certificates && \
-    wget -P /tmp https://github.com/$(curl -s -L https://github.com/chrislusf/seaweedfs/releases/latest | egrep -o '/chrislusf/seaweedfs/releases/download/.*/linux_amd64.tar.gz') && \
+# Tried to use curl only (curl -o /tmp/linux_amd64.tar.gz ...), however it turned out that the following tar command failed with "gzip: stdin: not in gzip format"
+RUN apk add --no-cache --virtual build-dependencies --update wget curl ca-certificates && \
+    wget -P /tmp https://github.com/$(curl -s -L https://github.com/chrislusf/seaweedfs/releases/latest | egrep -o 'chrislusf/seaweedfs/releases/download/.*/linux_amd64.tar.gz') && \
     tar -C /usr/bin/ -xzvf /tmp/linux_amd64.tar.gz && \
-    apk del curl wget ca-certificates build-dependencies && \
+    apk del build-dependencies && \
     rm -rf /tmp/*
 
 EXPOSE 8080