Document wasmtime-rb (#5485)

* Document wasmtime-rb

* Fix typo in `docs/lang-ruby.md`, improve copy

README.md

@@ -116,6 +116,7 @@ the implementation:
 * **[Python]** - the [`wasmtime` PyPI package]
 * **[.NET]** - the [`Wasmtime` NuGet package]
 * **[Go]** - the [`wasmtime-go` repository]
+* **[Ruby]** - the [`wasmtime` gem]
 
 [Rust]: https://bytecodealliance.github.io/wasmtime/lang-rust.html
 [C]: https://bytecodealliance.github.io/wasmtime/examples-c-embed.html
@@ -130,6 +131,8 @@ the implementation:
 [wasmtime-cpp]: https://github.com/bytecodealliance/wasmtime-cpp
 [`wasmtime` Conan package]: https://conan.io/center/wasmtime
 [`wasmtime-cpp` Conan package]: https://conan.io/center/wasmtime-cpp
+[Ruby]: https://bytecodealliance.github.io/wasmtime/lang-ruby.html
+[`wasmtime` gem]: https://rubygems.org/gems/wasmtime
 
 ## Documentation
 

docs/lang-ruby.md

@@ -0,0 +1,63 @@
+# Using WebAssembly from Ruby
+
+Wasmtime [is available on RubyGems](https://rubygems.org/gems/wasmtime) and can
+be used programmatically to interact with Wasm modules. This guide will go over
+installing the Wasmtime gem and running a simple Wasm module from Ruby.
+
+Make sure you've got Ruby 3.0 or newer installed locally, and we can get
+started!
+
+## Getting started and simple example
+
+First, copy this example WebAssembly text module into your project. It exports
+a function for calculating the greatest common denominator of two numbers.
+
+```wat
+{{#include ../examples/gcd.wat}}
+```
+
+Next, install the Wasmtime Ruby gems by either adding it your project's
+`Gemfile`:
+
+```bash
+bundle add wasmtime
+```
+
+Or by using the `gem` command directly:
+
+```bash
+gem install wasmtime
+```
+
+The gem has a Rust-based native extension, but thanks to precompiled gems, you
+should not have to compile anything. It'll just work!
+
+Now that you have the Wasmtime gem installed, let's create a Ruby script to
+execute the `gcd` module from before.
+
+```ruby
+require "wasmtime"
+
+engine = Wasmtime::Engine.new
+mod = Wasmtime::Module.from_file(engine, "gcd.wat")
+store = Wasmtime::Store.new(engine)
+instance = Wasmtime::Instance.new(store, mod)
+
+puts "gcd(27, 6) = #{instance.invoke("gcd", 27, 6)}"
+```
+
+This script should output
+
+```bash
+gcd(27, 6) = 3
+```
+
+If this is the output you see, congrats! You've successfully ran your first
+WebAssembly code in Ruby!
+
+## More examples and contributing
+
+To learn more, check out the [more advanced examples](https://github.com/bytecodealliance/wasmtime-rb/tree/main/examples)
+and the [API documentation](https://bytecodealliance.github.io/wasmtime-rb/latest/).
+If you have any questions, do not hesitate to open an issue on the
+[GitHub repository](https://github.com/bytecodealliance/wasmtime-rb).

docs/stability-release.md

@@ -56,6 +56,7 @@ release is made, such as:
 * [`wasmtime-py`](https://github.com/bytecodealliance/wasmtime-py)
 * [`wasmtime-go`](https://github.com/bytecodealliance/wasmtime-go)
 * [`wasmtime-cpp`](https://github.com/bytecodealliance/wasmtime-cpp)
+* [`wasmtime-rb`](https://github.com/bytecodealliance/wasmtime-rb)
 
 Note, though, that bugs and security issues in these projects do not at this
 time warrant patch releases for Wasmtime.