update documentation

CHANGELOG.md

@@ -1,13 +1,15 @@
 # Change Log
 All notable changes to this project will be documented in this file.
 
-The format is based on [Keep a Changelog](http://keepachangelog.com/).
+The format is based on [Keep a Changelog](http://keepachangelog.com/)
+and this project adheres to [Semantic Versioning](http://semver.org/).
 
-## [Unreleased]
+## [0.4.0]
 
 ### Added
 - Tx#data_bin returns the data field of a transaction in binary.
 - Tx#data_hex returns the data field of a transaction as a hexadecimal string.
+- Tx#id is an alias of Tx#hash
 
 ### Changed
 - Tx#data is configurable to return either hex or binary: `config.tx_data_hex = true`.
@@ -16,3 +18,4 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).
 - Key#address getter is prepended by '0x'.
 - Extract public key to address method into Utils.public_key_to_address.
 - Tx#from returns an address instead of a public key.
+- Chain ID is updated to the later version of the spec.

README.md

@@ -36,10 +36,10 @@ Build a transaction from scratch:
 ```ruby
 tx = Eth::Tx.new({
   data: hex_data,
-  gas_limit: 3_141_592,
-  gas_price: 20_000_000_000,
+  gas_limit: 21_000,
+  gas_price: 3_141_592,
   nonce: 1,
-  to: key.address,
+  to: key2.address,
   value: 1_000_000_000_000,
 })
 ```
@@ -50,9 +50,9 @@ tx = Eth::Tx.decode hex
 
 ### Configure
 In order to prevent replay attacks, you must specify which Ethereum chain your transactions are created for. See [EIP 155](https://github.com/ethereum/EIPs/issues/155) for more detail.
-```
+```ruby
 Eth.configure do |config|
-  config.chain_id = 18 #defaults to 13
+  config.chain_id = 1 # nil by default, meaning valid on any chain
 end
 ```
 
@@ -65,7 +65,19 @@ Get the raw transaction with `tx.hex`, and broadcast it through any Ethereum nod
 
 ## Contributing
 
-Bug reports and pull requests are welcome on GitHub at https://github.com/se3000/ethereum-tx.
+Bug reports and pull requests are welcome on GitHub at https://github.com/se3000/ethereum-tx. Tests are encouraged.
+
+### Tests
+
+First install the [Ethereum common tests](https://github.com/ethereum/tests):
+```shell
+git submodule update --init
+```
+
+Then run the associated tests:
+```shell
+rspec
+```
 
 
 ## License