rust: Adopt .tool-versions and standardise scripts for Rust

rust/.gitignore

@@ -0,0 +1,2 @@
+# Cargo build output
+/target

rust/.tool-versions

@@ -0,0 +1 @@
+rust 1

rust/README.md

@@ -1,14 +1,29 @@
 # Rust
 
-Skeleton project for Rust.\
-It is assumed that Rust is installed on your machine. If not, please follow the [installation guide](https://www.rust-lang.org/tools/install).
+Skeleton project for Rust.
+
+## Prerequisites
+
+The toolchain this project needs is declared in [`.tool-versions`](./.tool-versions):
+
+```
+rust 1
+```
+
+Install those however you prefer, as long as they end up on your `PATH`. The quickest route is
+[mise](https://mise.jdx.dev/), which reads the file for you:
+
+```sh
+mise install
+```
 
 ## Usage
+- `./script/setup` to fetch dependencies
 - `./script/test` to run the tests
-- `./script/start` to run the code
+- `./script/start` to run the app
 
 ## Structure
 - Code located in [`main.rs`](./src/main.rs)
 - Tests located in [`lib.rs`](./src/lib.rs)
 
-However, you're free to organise your code as you like. 
+However, you're free to organise your code as you like.

rust/script/setup

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+cd "$(dirname "${BASH_SOURCE[0]}")/.."
+
+cargo fetch

rust/script/start

@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
 
-set -e
+set -euo pipefail
+
+cd "$(dirname "${BASH_SOURCE[0]}")/.."
 
 cargo run

rust/script/test

@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
 
-set -e
+set -euo pipefail
+
+cd "$(dirname "${BASH_SOURCE[0]}")/.."
 
 cargo test