Merge pull request grpc-ecosystem#22 from jchoffmann/master

Add grpc-json-proxy to Tools section

readme.md

@@ -83,6 +83,7 @@
 - [danby](https://github.com/ericbets/danby) - A grpc proxy for the browser 
 - [docker-protoc](https://github.com/namely/docker-protoc) - Dockerized protoc, grpc-gateway, and grpc_cli commands bundled with Google API libraries
 - [ghz](https://github.com/bojand/ghz) - Simple gRPC benchmarking and load testing tool inspired by hey and grpcurl 
+- [grpc-json-proxy](https://github.com/jnewmano/grpc-json-proxy) - A proxy which allows existing tools like Postman or curl to interact with gRPC servers
 
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