ens-usernames/config/contracts.json

{
  "default": {
    "versions": {
      "web3.js": "1.0.0-beta",
      "solc": "0.4.23"
    },
    "deployment": {
      "host": "localhost",
      "port": 8545,
      "type": "rpc"
    },
    "dappConnection": [
      "$WEB3",
      "http://localhost:8545"
    ],
    "gas": "auto",
    "contracts": {
    }
  }
}