added Docker support with env variables

Dockerfile

@@ -0,0 +1,18 @@
+FROM node:18-alpine
+
+# Create app directory
+WORKDIR /usr/src/app
+
+# Install app dependencies
+# A wildcard is used to ensure both package.json AND package-lock.json are copied
+# where available (npm@5+)
+COPY package*.json ./
+
+RUN npm install
+# If you are building your code for production
+# RUN npm ci --omit=dev
+
+# Bundle app source
+COPY . .
+
+CMD [ "node", "." ]