Add link out to synapse modeul

Author: hughns

README.md

@@ -1,7 +1,5 @@
 # Rust HTTP Rendezvous Server
 
-Like https://github.com/matrix-org/node-http-rendezvous-server but in Rust
-
 An implementation of [MSC3886: Simple rendezvous capability](https://github.com/matrix-org/matrix-spec-proposals/pull/3886) that can be used standalone or packaged as a Synapse module.
 
 Functionality constraints:
@@ -10,6 +8,12 @@ Functionality constraints:
 - the server does not need to work in a clustered/sharded deployment
 - no authentication is needed for use of the server
 
+## Installation
+
+For instructions on usage as a Synapse module, see [matrix-http-rendezvous-synapse](https://pypi.org/project/matrix-http-rendezvous-synapse/) on PyPI.
+
+## Contributing
+
 ### Releasing
 
 ```sh