truffle-config.js

const HDWalletProvider = require("truffle-hdwallet-provider");
const secrets          = require("./secrets.js");

module.exports = {
  networks: {
    ropsten: {
      provider: () => new HDWalletProvider(secrets.ropsten.mnemonic, `https://ropsten.infura.io/v3/${secrets.infura.projectId}`),
      network_id: 3,       // Ropsten's id
      gas: 5500000,        // Ropsten has a lower block limit than mainnet
      confirmations: 2,    // # of confs to wait between deployments. (default: 0)
      timeoutBlocks: 200,  // # of blocks before a deployment times out  (minimum/default: 50)
      skipDryRun: true     // Skip dry run before migrations? (default: false for public nets )
    },

    mainnet: {
      provider: () => new HDWalletProvider(secrets.mainnet.mnemonic, `https://mainnet.infura.io/v3/${secrets.infura.projectId}`),
      network_id: 1,       // Ropsten's id
      gas: 5500000,        // Ropsten has a lower block limit than mainnet
      confirmations: 3,    // # of confs to wait between deployments. (default: 0)
      timeoutBlocks: 200,  // # of blocks before a deployment times out  (minimum/default: 50)
      skipDryRun: true     // Skip dry run before migrations? (default: false for public nets )
    },
  },

  // Set default mocha options here, use special reporters etc.
  mocha: {
    // timeout: 100000
  },

  // Configure your compilers
  compilers: {
    solc: {
      version: "0.5.0",    // Fetch exact version from solc-bin (default: truffle's version)
      docker: false,       // Use "0.5.1" you've installed locally with docker (default: false)
      settings: {          // See the solidity docs for advice about optimization and evmVersion
       optimizer: {
         enabled: false,
         runs: 200
       },
       evmVersion: "byzantium"
      }
    }
  }
}