use non-caching dockerfile

* LukeMathWalker/zero-to-production#71 (comment)

Dockerfile

@@ -1,33 +1,17 @@
-FROM rust:1.47 AS planner
+FROM rust:1.50 AS builder
 WORKDIR app
-RUN cargo install cargo-chef --version 0.1.6
-COPY . .
-RUN cargo chef prepare --recipe-path recipe.json
-
-FROM rust:1.47 AS cacher
-WORKDIR app
-RUN cargo install cargo-chef --version 0.1.6
-COPY --from=planner /app/recipe.json recipe.json
-RUN RUST_BACKTRACE=1 cargo chef cook --release --recipe-path recipe.json
-
-FROM rust:1.47 AS builder
-WORKDIR app
-COPY --from=cacher /app/target target
-COPY --from=cacher /usr/local/cargo /usr/local/cargo
 COPY . .
 ENV SQLX_OFFLINE true
 RUN cargo build --release --bin zero2prod
 
 FROM debian:buster-slim AS runtime
 WORKDIR app
-# OpenSSL is dynamically linked by some dependencies
-RUN apt-get update -y \
-    && apt-get install -y --no-install-recommends openssl \
-    # Cleanup
-    && apt-get autoremove -y \
-    && apt-get clean -y \
+RUN apt-get update -y
+    && apt-get install -y --no-install-recommends openssl
+    && apt-get autoremove -y
+    && apt-get clean -y
     && rm -rf /var/lib/apt/lists/*
-COPY --from=builder /app/target/release/zero2prod ./zero2prod
+COPY --from=builder /app/target/release/zero2prod zero2prod
 COPY configuration configuration
 ENV APP_ENVIRONMENT production
 ENTRYPOINT ["./zero2prod"]