Request: chainId Option

[aakilfernandes]

Expected Behavior

chainId should be an option

Current Behavior

eth_chainId rpc call is implemented, but there's no way to set a custom chainId.

[davidmurdoch]

Thanks for opening this issue, @aakilfernandes. This is a feature that will ship in the next version. We are tracking it here: trufflesuite/ganache#451 for a list of other breaking changes (this one is breaking because of a bug with how Ganache treats chainId internally).