added caddy

backend/Dockerfile

@@ -0,0 +1,22 @@
+# ── Build ───────────────────────────────────────────────────
+FROM rust:1-bookworm AS build
+WORKDIR /app
+
+# Cache deps: copy manifests, build a stub, then the real source.
+COPY Cargo.toml Cargo.lock ./
+RUN mkdir src && echo "fn main() {}" > src/main.rs \
+    && cargo build --release \
+    && rm -rf src
+
+COPY . .
+# Touch so cargo rebuilds with the real main.rs.
+RUN touch src/main.rs && cargo build --release
+
+# ── Runtime ─────────────────────────────────────────────────
+FROM debian:bookworm-slim AS runtime
+WORKDIR /app
+RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+COPY --from=build /app/target/release/shoplist-backend /usr/local/bin/shoplist-backend
+EXPOSE 8080
+CMD ["shoplist-backend"]