Add README.md

README.md

+# Rust Base Image
+
+Rust base image for use in Gitlab CI. Includes extra tools to support the CI use case
+
+## Usage
+
+To use this image as the base for your CI pipeline, include the following at the head of your `.gitlab-ci.yml`:
+
+```yaml
+image: cr.weirdboi.dev/base/rust:1.82
+```
+
+To use this image for a specific pipeline job, include the following in your job spec:
+
+```yaml
+my_build_step:
+  stage: build
+  image: cr.weirdboi.dev/base/rust:1.82
+  script:
+    # ...
+```
+
+## Additional Tools
+
+### Rustup
+
+- Rustup is installed and configured using the default profile, which includes `fmt` and `clippy`.
+- Only the default linux x86-64 toolchain is installed
+- Stable rust is the default version, where the image tag dictates which rust version is being used
+- Nightly rust is installed, where the version is based on the build time of the image
+
+### Cargo Tools
+
+- `cargo binstall` - Install prebuilt binaries from crates.io
+- `cargo nextest` - Efficient testing
+
+### Extra Binaries
+
+- `junitify` - Can be used to transform the output of `cargo test` into a junit.xml file
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