update ibc-client-tendermint-cw README

ibc-clients/ics07-tendermint/cw-contract/README.md

@@ -1,18 +1,45 @@
-# `cw-contract` crate
+# `ibc-client-tendermint-cw` crate
 
-This crate showcases a barebones CosmWasm contract implementation utilizing the `ibc-client-cw`
-crate, which exposes the requisite interfaces needed to implement contracts on top of `ibc-rs`.
+This crate showcases how to reuse `ibc-rs` light clients as a
+[CosmWasm contract](https://github.com/cosmos/ibc/blob/main/spec/client/ics-008-wasm-client/README.md)
+utilizing the `ibc-client-cw` crate.
 
-The following template can be used to get you started:
+The `ibc-client-cw` crate exposes the requisite types and traits needed to reuse
+the `ibc-rs` light clients. Notably, it offers a
+[`ClientType`](https://docs.rs/ibc-client-cw/latest/ibc_client_cw/api/trait.ClientType.html)
+trait, which requires two associated types: `ClientState` and `ConsensusState`.
+These types take any type that implements the
+[`ClientStateExecution`](https://docs.rs/ibc-core/latest/ibc_core/client/context/client_state/trait.ClientStateExecution.html)
+and
+[`ConsensusState`](https://docs.rs/ibc-core/latest/ibc_core/client/context/consensus_state/trait.ConsensusState.html)
+traits from the `ibc-core` crate.
+
+For example, to reuse the existing
+[`ibc-client-tendermint`](https://docs.rs/ibc-client-tendermint/latest/ibc_client_tendermint/):
 
 ```rs
+use ibc_client_cw::api::ClientType;
+use ibc_client_tendermint::client_state::ClientState;
+use ibc_client_tendermint::consensus_state::ConsensusState;
+
 #[derive(Clone, Debug)]
 pub struct TendermintClient;
 
 impl<'a> ClientType<'a> for TendermintClient {
     type ClientState = ClientState;
     type ConsensusState = ConsensusState;
 }
+```
+
+Once the `ClientType` trait is implemented, the `ibc-client-cw` crate can be
+used to complete the entry points for the CosmWasm contract:
+
+```rs
+use cosmwasm_std::{entry_point, Binary, Deps, DepsMut, Env, MessageInfo, Response};
+use ibc_client_cw::context::Context;
+use ibc_client_cw::types::{ContractError, InstantiateMsg, QueryMsg, SudoMsg};
+
+pub type TendermintContext<'a> = Context<'a, TendermintClient>;
 
 #[entry_point]
 pub fn instantiate(
@@ -39,3 +66,6 @@ pub fn query(deps: Deps<'_>, env: Env, msg: QueryMsg) -> Result<Binary, Contract
     ctx.query(msg)
 }
 ```
+
+The above snippets compile into a fully working CosmWasm contract implementing
+Tendermint IBC light client.