Fix Dockerfile

Mage uses git, so we should install git before run mage.

Closes #9261

diff --git a/Dockerfile b/Dockerfile
index 473296ad04824a009804254596f597bb42edcf05..fcae03f5484557733d02a7bd14f1c804e7bc2bbf 100755 (executable)
--- a/Dockerfile
+++ b/Dockerfile
@@ -19,7 +19,7 @@ COPY . /go/src/github.com/gohugoio/hugo/
 
 # gcc/g++ are required to build SASS libraries for extended version
 RUN apk update && \
-    apk add --no-cache gcc g++ musl-dev && \
+    apk add --no-cache gcc g++ musl-dev git && \
     go get github.com/magefile/mage
 
 RUN mage hugo && mage install