Add information about truffle migrate quirk

[asselstine]

module.exports = async function(deployer) {
let delegateKey = stringTo32Bytes('CryptoTrophies')
let targetKey = stringTo32Bytes('CryptoTrophiesTarget')
deployer.then(function () {
return Registry.deployed().then((instance) => {
return deployer.deploy(Delegate, instance.address, targetKey)
})
})
}