docs: Document how to use rules_cuda with Bzlmod (#252)

README.md

@@ -6,6 +6,8 @@ These rules provide some macros and rules that make it easier to build CUDA with
 
 ## Getting Started
 
+### Traditional WORKSPACE approach
+
 Add the following to your `WORKSPACE` file and replace the placeholders with actual values.
 
 ```starlark
@@ -29,11 +31,35 @@ ensure the host compiler is available. On Windows, this means that you will also
 and [`detect_clang`](https://github.com/bazel-contrib/rules_cuda/blob/5633f0c0f7/cuda/private/repositories.bzl#L143-L166)
 determains how the toolchains are detected.
 
+### Bzlmod
+
+Add the following to your `MODULE.bazel` file and replace the placeholders with actual values.
+
+```starlark
+bazel_dep(name = "rules_cuda", version = "0.2.1")
+
+# pick a specific version (this is optional an can be skipped)
+archive_override(
+    module_name = "rules_cuda",
+    integrity = "{sha256_to_replace}",
+    urls = "https://github.com/bazel-contrib/rules_cuda/archive/{git_commit_hash}.tar.gz",
+    strip_prefix = "rules_cuda-{git_commit_hash}",
+)
+
+cuda = use_extension("@rules_cuda//cuda:extensions.bzl", "toolchain")
+cuda.local_toolchain(
+    name = "local_cuda",
+    toolkit_path = "",
+)
+use_repo(cuda, "local_cuda")
+```
+
 ### Rules
 
 - `cuda_library`: Can be used to compile and create static library for CUDA kernel code. The resulting targets can be
   consumed by [C/C++ Rules](https://bazel.build/reference/be/c-cpp#rules).
-- `cuda_objects`: If you don't understand what _device link_ means, you must never use it. This rule produces incomplete object files that can only be consumed by `cuda_library`. It is created for relocatable device code and device link
+- `cuda_objects`: If you don't understand what _device link_ means, you must never use it. This rule produces incomplete
+  object files that can only be consumed by `cuda_library`. It is created for relocatable device code and device link
   time optimization source files.
 
 ### Flags
@@ -96,7 +122,7 @@ Checkout the examples to see if it fits your needs.
 
 See [examples](./examples) for basic usage.
 
-See [rules_cuda_examples](https://github.com/cloudhan/rules_cuda_examples) for extended real world projects.
+See [rules_cuda_examples](https://github.com/cloudhan/rules_cuda_examples) for extended real-world projects.
 
 ## Known issue