chore(docker): add docker compose deployment

Dockerfile.backend

@@ -0,0 +1,36 @@
+# syntax=docker/dockerfile:1
+
+FROM ubuntu:24.04 AS build
+
+RUN apt-get update -y && \
+    DEBIAN_FRONTEND=noninteractive apt-get install -y \
+      build-essential cmake ninja-build pkg-config \
+      libdrogon-dev libjsoncpp-dev libyaml-cpp-dev libhiredis-dev \
+      libpq-dev libmariadb-dev libmariadb-dev-compat \
+      libsqlite3-dev sqlite3 \
+      libssl-dev && \
+    rm -rf /var/lib/apt/lists/*
+
+WORKDIR /src
+COPY backend/ ./backend/
+COPY CMakeLists.txt ./
+
+RUN cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release && \
+    cmake --build build --target csp_server
+
+
+FROM ubuntu:24.04 AS runtime
+
+RUN apt-get update -y && \
+    DEBIAN_FRONTEND=noninteractive apt-get install -y \
+      libdrogon1t64 libjsoncpp25 libyaml-cpp0.8 libhiredis1.1.0 \
+      libpq5 libmariadb3 libsqlite3-0 libssl3t64 ca-certificates && \
+    rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+COPY --from=build /src/build/backend/csp_server /app/csp_server
+
+EXPOSE 8080
+
+# DB file mounted by compose at /data/csp.db
+CMD ["/app/csp_server", "/data/csp.db"]