add links to README; reformat repo

README.md

@@ -1,2 +1,24 @@
 # Getting Started with the Pub/Sub API
-Sample project to get started with the Pub/Sub API API
+
+Welcome to the Pub/Sub API Pilot! This repo contains the critical [proto
+file](https://github.com/developerforce/pub-sub-api-pilot/blob/main/pubsub_api.proto)
+that you will need to use the API. Refer to the pilot guide on how to use it.
+
+gRPC [officially supports 11 languages](https://grpc.io/docs/languages/), but
+there is unofficial community support in more. To encode and decode events, an
+Avro library for your language of choice will be needed. See below for which
+gRPC-support languages have well-supported Avro libraries:
+
+|Supported gRPC Language|Avro Libraries|
+|-----------------------|--------------|
+|C# | [AvroConvert](https://github.com/AdrianStrugala/AvroConvert)<br />[Apache Avro C#](https://avro.apache.org/docs/current/api/csharp/html/index.html) (docs are not great)|
+|C++|[Apache Avro C++](https://avro.apache.org/docs/current/api/cpp/html/index.html)|
+|Dart|[avro-dart](https://github.com/sqs/avro-dart) (last updated 2012)|
+|Go|[goavro](https://github.com/linkedin/goavro)|
+|Java|[Apache Avro Java](https://avro.apache.org/docs/1.10.2/gettingstartedjava.html)|
+|Kotlin|[avro4k](https://github.com/avro-kotlin/avro4k)|
+|Node|[avro-js](https://www.npmjs.com/package/avro-js)|
+|Objective C|[ObjectiveAvro](https://github.com/jlawton/ObjectiveAvro) (but read [this](https://stackoverflow.com/questions/57216446/data-serialisation-in-objective-c-avro-alternative))|
+|PHP|[avro-php](https://github.com/wikimedia/avro-php)|
+|Python|[Apache Avro Python](https://avro.apache.org/docs/current/gettingstartedpython.html)|
+|Ruby|[AvroTurf](https://github.com/dasch/avro_turf)|