Refactor Dockerfile for multi-stage build

tools/docker/Dockerfile

@@ -1,8 +0,0 @@
-FROM alpine:latest
-RUN apk add cargo && wget -O source.tar.gz $(wget -qO- https://api.github.com/repos/mbrubeck/agate/releases/latest | sed -nE 's/^.*"tarball_url"\s*:\s*"([^"]+)".*$/\1/p')&& tar xzf source.tar.gz && mv /mbrubeck-agate-* /agate && cd agate && cargo build --release
-RUN cp /agate/target/release/agate /usr/bin/agate
-WORKDIR /app
-COPY . /app
-ADD . .
-ENTRYPOINT ["/bin/sh", "start.sh"]
-

tools/docker/start.sh

@@ -1,6 +1,8 @@
 #!/bin/sh
 
-exec agate --content /gmi/ \
-	--hostname ${HOSTNAME} \
-	--lang ${LANG}
+echo "Using hostname ${HOSTNAME:-localhost}"
+echo "Using lang ${LANG:-en-US}"
 
+exec agate --content /gmi/ \
+	--hostname "${HOSTNAME:-localhost}" \
+	--lang "${LANG:-en-US}"