Update README with Ubuntu usage instructions and additional information.

README.md

@@ -1,10 +1,21 @@
-# rustls-openssl-compat
+# Rustls OpenSSL Compatibility Layer
 
-This is the planned home of several rustls to OpenSSL compatibility layers.
-Currently here:
+This is an implementation of the OpenSSL libssl ABI which uses [Rustls](https://github.com/rustls/rustls/) for TLS.
 
-- **[rustls-libssl](rustls-libssl/)**: an implementation of the OpenSSL libssl ABI in terms of rustls.
+## Use With Nginx on Ubuntu
 
-Not yet here:
+Initially we targeted support for use with Nginx on Ubuntu 22.04 or higher. It's very simple to replace Nginx usage of OpenSSL with Rustls on Ubuntu:
 
-- **rustls-libcrypto**: an implementation of rustls `CryptoProvider` in terms of OpenSSL's libcrypto.
+```
+$ wget https://github.com/rustls/rustls-openssl-compat/releases/latest/download/rustls-libssl_amd64.deb
+$ sudo dpkg -i rustls-libssl_amd64.deb
+$ sudo rustls-libssl-nginx enable
+$ sudo systemctl daemon-reload
+$ sudo service nginx restart
+```
+
+## Future
+
+* Simple Fedora-based packaging and instructions.
+* Additional libssl ABI surface implementation.
+* Provide an implementation of OpenSSL's libcrypto ABI which uses rustls `cryptoprovider`.