Update README.md

Author: willemneal

README.md

@@ -20,10 +20,17 @@ just build
 ```
 just deploy contract-a
 ```
+Or snake_case
+```
+just deploy contract_a
+```
 
 ## invoke contracts
 
 ```bash
 just invoke contract-a --help
 ```
 
+Currently the `.env` file has `SOROBAN_NETWORK=testnet`.
+
+To use local first start the local docker `just network_start`. Then either change `.env`, use `export SOROBAN_NETWORK=local` or prefix your just commands with `SOROBAN_NETWORK=local`. e.g. `SOROBAN_NETWORK=local just deploy contract-a`