Add pm2 to make server production ready

Author: kmehant

Dockerfile.prod

@@ -8,7 +8,9 @@ RUN git clone https://github.com/codeuino/social-platform-donut-backend.git
 
 WORKDIR /server/social-platform-donut-backend
 
-RUN npm install && npm cache clean --force --loglevel=error
+RUN npm install && \
+    npm install pm2@latest -g && \
+    npm cache clean --force --loglevel=error
 
 # Start the server
-CMD [ "npm", "start" ]
+CMD [ "pm2", "start", "./bin/www", "--time", "--no-daemon" ]