updated Dockerfile to run app.js entrypoint

Dockerfile

@@ -1,17 +1,12 @@
 FROM node:carbon
 
 # Create app directory
-WORKDIR /usr/src/app
+RUN mkdir /app
+WORKDIR /app
 
-# Install app dependencies
-# A wildcard is used to ensure both package.json AND package-lock.json are copied
-# where available (npm@5+)
+ADD src ./src
+ADD config ./config
 COPY package*.json ./
 
 RUN npm install
-
-# Bundle app source
-COPY . .
-
-EXPOSE 3000
-CMD [ "npm", "start" ]
+CMD ["node", "./src/app.js"]