add a Dockerfile

Signed-off-by: Jakub Sokołowski <jakub@status.im>

Dockerfile

@@ -0,0 +1,20 @@
+FROM node:8.12-slim
+
+WORKDIR /app
+
+COPY package.json ./
+RUN npm install --only=production
+
+COPY src/ ./src/
+COPY .babelrc ./
+
+ENV REDIS_HOST=localhost \
+    REDIS_PORT=6379 \
+    LISTEN_PORT=3000
+
+LABEL source="https://github.com/status-im/clicks-counter" \
+      description="Basic NodeJS API for counting clicks." \
+      maintainer="jakub@status.im"
+
+CMD ["npm", "start"]
+EXPOSE $LISTEN_PORT