add dockerfile for production deployment

Dockerfile

@@ -0,0 +1,19 @@
+# Production Environment Dockerfile
+
+# base image
+FROM node:alpine
+
+# create & set working directory
+RUN mkdir -p /app
+WORKDIR /app
+
+# copy source files
+COPY . /app
+
+# install dependencies
+RUN npm install
+
+# start app
+RUN npm run build
+EXPOSE 3000
+CMD npm run start