Add the Dockerfile definition for the build and running of the application.

chat-app/Dockerfile

@@ -0,0 +1,18 @@
+FROM oven/bun:1 AS base
+WORKDIR /usr/src/app
+
+FROM base AS install 
+RUN mkdir -p /temp/build
+COPY package.json bun.lockb /temp/build/
+RUN cd /temp/build && bun install --frozen-lockfile
+
+FROM base AS release
+COPY --from=install /temp/build/node_modules node_modules
+COPY . .
+
+ENV NODE_ENV=production
+RUN bun run build
+
+USER bun
+EXPOSE 3000/tcp
+ENTRYPOINT [ "bun", "run", "src/index.ts" ]