truffle-smart-contract/truffle-config.js/0.0.6

truffle-config.js

const HDWalletProvider = require('truffle-hdwallet-provider-privkey');
const privateKey = "private-key-goes-here";
const endpointUrl = "endpoint-goes-here";

module.exports = {
  networks: {
    development: {
      host: "127.0.0.1",
      port: 7545,
      network_id: "5777",
    },
    kovan: {
      provider: function() {
        return new HDWalletProvider(
          //private keys array
          [privateKey],
          //url to ethereum node
          endpointUrl
        )
      },
      gas: 5000000,
      gasPrice: 25000000000,
      network_id: 42
    }
  }
}