diff --git a/Dockerfile b/Dockerfile
index a173e9e..1d69a6b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,15 +1,19 @@
-FROM node:8.1.2
+FROM node:7.9.0
 
+ARG PORT=9696
+ENV PORT=$PORT
 ENV HOME /home
+
+
 RUN mkdir -p $HOME
 WORKDIR $HOME
 
-COPY package.json package-lock.json ./
+COPY package.json ./
 
 RUN npm install
 
 COPY . .
 
-EXPOSE 9696
+EXPOSE $PORT
 
 CMD ["npm", "run", "start"]
diff --git a/circle.yml b/circle.yml
index dc50261..4543959 100644
--- a/circle.yml
+++ b/circle.yml
@@ -1,6 +1,6 @@
 machine:
   node:
-    version: 8.1.2
+    version: 7.9.0
   environment:
     DOCKER_IMAGE_NAME: stefanwalther/speedtest-exporter
     REPO_PATH: github.com/stefanwalther/speedtest-exporter
@@ -8,13 +8,12 @@ machine:
     - docker
 
 dependencies:
-  pre:
-    - docker build --rm=false -t ${DOCKER_IMAGE_NAME} .
   override:
     - npm install
 
 test:
   override:
+    - docker build --rm=false -t ${DOCKER_IMAGE_NAME} .
     - while ! curl --retry 10 --retry-delay 5 -v http://0.0.0.0:9696 >/dev/null; do sleep 1; done
 
 deployment: