Fix automated build

Dockerfile

@@ -1,17 +1,21 @@
 FROM alpine:3.5
 MAINTAINER Julien Del-Piccolo <julien@del-piccolo.com>
 ARG BRANCH="master"
+ARG COMMIT=""
 LABEL branch=${BRANCH}
+LABEL commit=${COMMIT}
 
 RUN apk update && apk add --no-cache supervisor apache2 php5-apache2 php5-ctype \
  && apk add --virtual=.build-dependencies php5 php5-phar php5-json php5-openssl git \
- && rm -rf /var/www/localhost/htdocs \
- && git clone -b ${BRANCH} https://github.com/jdel/sspks.git /var/www/localhost/htdocs \
+ && rm -rf /var/www/localhost/htdocs/* \
+ && cd /var/www/localhost/htdocs/ \
+ && git init && git remote add origin https://github.com/jdel/sspks.git \
+ && git fetch origin ${COMMIT} \
  && wget -q -O /usr/local/bin/composer http://getcomposer.org/download/1.3.1/composer.phar \
  && chmod +x /usr/local/bin/composer \
  && cd /var/www/localhost/htdocs \
- && if [ -f composer.json ]; then composer install --no-dev; fi \
- && rm -f /usr/local/bin/composer \
+ && composer install --no-dev \
+  ; rm -f /usr/local/bin/composer \
  && apk del .build-dependencies \
  && rm -rf /var/cache/apk/* \
  && mkdir /run/apache2 \

hooks/build

@@ -1,3 +1,7 @@
 #!/usr/bin/env sh
 
-docker build --build-arg=BRANCH=$(git rev-parse --abbrev-ref HEAD) -t $IMAGE_NAME .
+if [ -z "${DOCKER_TAG}" ]; then
+  docker build --build-arg=COMMIT=$(git rev-parse HEAD) --build-arg=BRANCH=$(git rev-parse --abbrev-ref HEAD) -t $IMAGE_NAME .
+else
+  docker build --build-arg=COMMIT=$(git rev-parse HEAD) --build-arg=BRANCH=${DOCKER_TAG} -t $IMAGE_NAME .
+fi