feat: add a Dockerfile for image building

Dockerfile

@@ -0,0 +1,19 @@
+# Credit: https://www.digitalocean.com/community/tutorials/how-to-build-a-node-js-application-with-docker
+
+FROM node:22-alpine AS builder
+
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci --only=production && npm cache clean --force
+COPY . .
+
+FROM node:22-alpine AS production
+
+WORKDIR /app
+RUN addgroup -g 1001 -S nodejs && \
+    adduser -S js -u 1001
+COPY --from=builder --chown=js:nodejs /app /app
+USER js
+EXPOSE 6567
+
+CMD ["npm", "run", "server"]