doc: Update README

README.md

@@ -2,14 +2,37 @@
 Redis over QUIC with improved connection management
 
 
-## Building the proxy
+## Rationale
+
+Curently, the official Redis client for PYthon, `redis-py` has many issues (ref: redis/redis-py#3008) regarding connection, retry, and timeout management.
+Most problems are highlghy coupled to the API design, and it is hard to fix them without breaking the backward compatibility.
+When it comes to HA configurations using sentinels, it is very difficult to distinguish the different stages of the connection setup process.
+
+The target of this project is to:
+
+* Offload the connection pool management to QUIC by adopting light-weight streams bound to local UNIX socket connections of the Redis server.
+  - Make Redis client connections volatile, transient, light-weight QUIC streams.
+  - Split the fault isolation domain of networking into the localhost of Redis server and the QUIC remote networking, instead of coupling them together as in the conventional TCP-based connection pooling.
+* Achieve potentiall higher performance by eliminating handshake overheads when using secure TLS connections via public networks.
+* Provide a working, ready-to-try client implementation for potential future QUIC adoption in the Redis project ([redis/redis#6301](https://github.com/redis/redis/issues/6301)).
+
+
+## Development
+
+### Editable installation
+
+```sh
+pip install -U -e '.[lint,typecheck,test,build,docs]'
+```
+
+### Building the reverse-proxy (QUIC to UNIX/TCP)
 
 ```sh
 cd src/qedis-proxy
 go build
 ```
 
-## Testing
+### Testing
 
 **Terminal 1:**
 ```sh