Add frontend deps caching in Dockerfile (#11)

Dockerfile

@@ -3,20 +3,22 @@ RUN cargo install cargo-chef
 RUN cargo install trunk
 RUN rustup target add wasm32-unknown-unknown
 
-FROM base as planner
-WORKDIR /usr/src/sumi
-COPY . .
-RUN cargo chef prepare --recipe-path recipe.json
-
 FROM base as cacher
 WORKDIR /usr/src/sumi
-COPY --from=planner /usr/src/sumi/recipe.json recipe.json
-RUN cargo chef cook --release --recipe-path recipe.json
+COPY ./Cargo.lock ./
+COPY ./Cargo.toml ./
+COPY ./frontend/Cargo.toml ./frontend/Cargo.toml
+COPY ./backend/Cargo.toml ./backend/Cargo.toml
+COPY ./frontend/.cargo ./frontend/.cargo
+RUN mkdir ./backend/src && mkdir ./frontend/src && echo 'fn main() { println!("Dummy"); }' > ./backend/src/main.rs && echo 'fn main() { println!("Dummy"); } ' > ./frontend/src/lib.rs
+RUN cargo build --release --manifest-path ./backend/Cargo.toml
+WORKDIR /usr/src/sumi/frontend
+RUN cargo build --release
 
 FROM base as builder
 WORKDIR /usr/src/sumi
-COPY . .
 COPY --from=cacher /usr/src/sumi/target target
+COPY . .
 RUN trunk build -d dist ./frontend/index.html --release
 RUN cargo build --manifest-path ./backend/Cargo.toml --release
 

frontend/.cargo/config.toml

@@ -0,0 +1,2 @@
+[build]
+target = "wasm32-unknown-unknown"