refactor: add Dockerfile multi stages

Dockerfile

@@ -1,11 +1,24 @@
-FROM rust:1-slim
-
+FROM rust:1 AS base
 WORKDIR /app
 
+FROM base AS dev 
+RUN cargo install cargo-watch
 COPY . .
+CMD ["cargo", "watch", "-x", "run"]
 
-RUN cargo build
+FROM base AS planner
+RUN cargo install cargo-chef
+COPY . .
+RUN cargo chef prepare  --recipe-path recipe.json
 
-EXPOSE 8000
+FROM base AS build
+COPY --from=planner /app/recipe.json recipe.json
+RUN cargo chef cook --release --recipe-path recipe.json
+COPY . .
+RUN cargo build --release --bin sudoku-rust
 
-CMD ["cargo", "run"]
+
+FROM debian:stable-slim AS prod
+WORKDIR /app
+COPY --from=build /app/target/release/sudoku-rust /usr/local/bin
+ENTRYPOINT ["/usr/local/bin/app"]

README.md

@@ -30,7 +30,11 @@ Go to the project directory
 Build the docker image
 
 ```bash
-  docker build -t sudoku-rust .
+  # with live reload
+  docker build -t sudoku-rust --target=dev .
+
+  # release optimized
+  docker build -t sudoku-rust --target=prod .
 ```
 
 Run the docker container