lock hugo to custom v0.53-DEV with docker

Dockerfile

@@ -0,0 +1,63 @@
+# Custom Hugo Extended fork, pre-built on Docker Hub:
+# https://hub.docker.com/r/jakejarvis/hugo-jarv.is
+# Source for base Dockerfile: https://go.jarv.is/30KA6DS
+#
+# Usage:
+#      docker build -t jarv.is:develop -f Dockerfile .
+#      docker run -v $(pwd):/src -p 1313:1313 jarv.is:develop
+# ...then open http://localhost:1313 for the live-refresh server.
+
+FROM golang:1.12-alpine AS builder
+
+ARG HUGO_REPO=https://github.com/jakejarvis/hugo.git
+# ARG HUGO_BRANCH=master
+# ARG HUGO_COMMIT=a28865c
+ARG HUGO_BUILD_TAGS=extended
+
+# CGO (and gcc/g++) required to build wellington/go-libsass
+ARG CGO=1
+ENV CGO_ENABLED=${CGO}
+ENV GOOS=linux
+ENV GO111MODULE=on
+
+RUN apk update && \
+    apk add --no-cache git gcc g++ musl-dev && \
+    git clone $HUGO_REPO $GOPATH/src/github.com/gohugoio/hugo && \
+    cd $GOPATH/src/github.com/gohugoio/hugo && \
+    if [ ! -z "$HUGO_BRANCH" ]; then git checkout $HUGO_BRANCH; fi && \
+    if [ ! -z "$HUGO_COMMIT" ]; then git reset --hard $HUGO_COMMIT; fi && \
+    go get github.com/magefile/mage && \
+    mage hugo && mage install && \
+    rm -rf $GOPATH/src
+
+# verify we've built correctly
+RUN /go/bin/hugo version
+
+# ---
+
+FROM alpine:3.10
+
+COPY --from=builder /go/bin/hugo /usr/bin/hugo
+
+# install libc6-compat & libstdc++ since we're building extended Hugo
+# https://gitlab.com/yaegashi/hugo/commit/22f0d5cbd6114210ba7835468facbdee60609aa2
+# Twitter oEmbed shortcode fails without ca-certificates (x509: certificate signed by unknown authority)
+# https://github.com/google/go-github/issues/1049
+RUN apk update && \
+    apk add --no-cache ca-certificates libc6-compat libstdc++ && \
+    update-ca-certificates
+
+# verify we've copied correctly
+RUN /usr/bin/hugo version
+
+# add site source as volume
+VOLUME /src
+WORKDIR /src
+
+# expose live-refresh server
+EXPOSE 1313
+
+ENTRYPOINT ["/usr/bin/hugo"]
+
+# remove before pushing to Docker Hub:
+CMD ["server", "--bind", "0.0.0.0", "--port", "1313"]