Add links to implementations in other lanugages (#49)

* Add links to implementations in other lanugages

The Go library is the reference implementation, though not everyone uses Go.
That's why it's useful to link to other implementations so people can use KSUID
in the language of their choice.

* README; move the implementations in other languages to the bottom

README.md

@@ -221,6 +221,14 @@ $ ksuid -f template -t '{ "timestamp": "{{ .Timestamp }}", "payload": "{{ .Paylo
 { "timestamp": "107611700", "payload": "67517BA309EA62AE7991B27BB6F2FCAC", "ksuid": "0uk1Ha7hGJ1Q9Xbnkt0yZgNwg3g"}
 ```
 
+## Implementations for other languages
+
+- Python: [svix-ksuid](https://github.com/svixhq/python-ksuid/)
+- Ruby: [ksuid-ruby](https://github.com/michaelherold/ksuid-ruby)
+- Java: [ksuid](https://github.com/ksuid/ksuid)
+- Rust: [rksuid](https://github.com/nharring/rksuid)
+- dotNet: [Ksuid.Net](https://github.com/JoyMoe/Ksuid.Net)
+
 ## License
 
 ksuid source code is available under an MIT [License](/LICENSE.md).