truffle.js

require('dotenv').config()
const HDWalletProvider = require("truffle-hdwallet-provider");
const MNEMONIC = process.env.MNEMONIC
const INFURA_KEY = process.env.INFURA_KEY

if (!MNEMONIC || !INFURA_KEY) {
  console.error("Please set a mnemonic and infura key.")
  return
}

const gasPrice = process.env.GAS_PRICE || 10000000000;

module.exports = {
  networks: {
    development: {
      host: "localhost",
      port: 8545,
      gas: 4600000,
      network_id: "*", // Match any network id,
      gasPrice
    },
    rinkeby: {
      provider: function() {
        return new HDWalletProvider(
          MNEMONIC,
          "https://rinkeby.infura.io/v3/" + INFURA_KEY,
          0, 5);
      },
      network_id: "*",
      gas: 4000000,
      gasPrice
    },
    mainnet: {
      network_id: 1,
      provider: function() {
        return new HDWalletProvider(
          MNEMONIC,
          "https://mainnet.infura.io/v3/" + INFURA_KEY,
          0, 5);
      },
      gas: 4000000,
      gasPrice
    }
  },
  mocha: {
    reporter: 'eth-gas-reporter',
    reporterOptions : {
      currency: 'USD',
      gasPrice: 2
    }
  },
  compilers: {
    solc: {
      version: "^0.5.0"
    }
  }
};