Mr. Drew's Assignment Creator — Docker share build

Self-contained Dockerized build for end users. Run via docker compose;
see README.md for setup. Source-only, no sample data or build artifacts.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docker/Dockerfile

@@ -0,0 +1,26 @@
+# Mr. Drew's Assignment Creator — production image.
+# Build context is the repository root:  docker build -f docker/Dockerfile .
+# (docker-compose.yml in this folder does that for you.)
+
+FROM node:20-alpine AS deps
+WORKDIR /app
+COPY package.json package-lock.json ./
+RUN npm ci
+
+FROM node:20-alpine AS build
+WORKDIR /app
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+RUN npm run build
+
+FROM node:20-alpine AS run
+WORKDIR /app
+ENV NODE_ENV=production HOSTNAME=0.0.0.0 PORT=3000
+# Next.js "standalone" output: a self-contained server, no node_modules needed.
+COPY --from=build /app/.next/standalone ./
+COPY --from=build /app/.next/static ./.next/static
+# The single-file database lives here — mounted as a volume by compose.
+RUN mkdir -p /app/data && chown -R node:node /app
+USER node
+EXPOSE 3000
+CMD ["node", "server.js"]