build: add caching for container image creation

Dockerfile

@@ -1,20 +1,33 @@
 # Builder stage
-FROM rust:1.75.0 AS builder
-
+FROM docker.io/lukemathwalker/cargo-chef:latest-rust-1.75.0 as chef
 WORKDIR /app
 RUN apt update && apt install lld clang -y
+
+FROM chef as planner
+COPY . .
+# Compute a lock-like file for our project
+RUN cargo chef prepare  --recipe-path recipe.json
+
+FROM chef as builder
+COPY --from=planner /app/recipe.json recipe.json
+# Build our project dependencies, not our application!
+RUN cargo chef cook --release --recipe-path recipe.json
+# Up to this point, if our dependency tree stays the same,
+# all layers should be cached. 
 COPY . .
 ENV SQLX_OFFLINE true
-RUN cargo build --release
-
-# Runtime stage
-FROM rust:1.75.0-slim AS runtime
+# Build our project
+RUN cargo build --release --bin zero2prod
 
+FROM docker.io/debian:bullseye-slim AS runtime
 WORKDIR /app
-# Copy the compiled binary from the builder environment 
-# to our runtime environment
+RUN apt-get update -y \
+    && apt-get install -y --no-install-recommends openssl ca-certificates \
+    # Clean up
+    && apt-get autoremove -y \
+    && apt-get clean -y \
+    && rm -rf /var/lib/apt/lists/*
 COPY --from=builder /app/target/release/learn_axum zero2prod
-# We need the configuration file at runtime!
 COPY configuration configuration
 ENV APP_ENVIRONMENT production
 ENTRYPOINT ["./zero2prod"]