Document what common-ts includes

packages/common-ts/README.md

@@ -2,6 +2,42 @@
 
 **NOTE: THIS PROJECT IS BETA SOFTWARE.**
 
+## Documentation
+
+`@graphprotocol/common-ts` is a TypeScript utility library for The Graph. It
+currently provides the following functionality:
+
+- Type-safe contract bindings to interact with The Graph Network on mainnet
+  and rinkeby.
+
+- Create query response attestations using
+  [EIP-712](https://eips.ethereum.org/EIPS/eip-712).
+
+- A GraphQL client to query The Graph Network network subgraph
+
+- Graph Token (GRT) formatting and parsing.
+
+- Validation and type-safe handling of subgraph deployment IDs.
+
+- Type-safe and normalized Ethereum addresses.
+
+Convenience features:
+
+- Security ehancement for [Express](https://expressjs.com/) web servers.
+
+- An easy-to-configure logger based on [pino](https://getpino.io/) with
+  support for asynchronous logging and [Sentry](https://sentry.io) error
+  reporting.
+
+- A consistent way of connecting to [Postgres](https://www.postgresql.org/)
+  using [Sequelize](https://sequelize.org/).
+
+- Easy-to-use [Prometheus](https://prometheus.io/) metrics client and server.
+
+- Eventuals: Asynchronously resolved, observable values that only emit values
+  if they have changed. These are convenient to monitor, for instance, Graph
+  Network data and only perform an action if it has changed.
+
 ## Copyright
 
 Copyright © 2020 The Graph Foundation.