truffle.js

module.exports = {
  networks: {
    coverage: {
      host: 'localhost',
      network_id: '*', // eslint-disable-line camelcase
      port: 8555,
      gas: 0xfffffffffff,
      gasPrice: 0x01,
    },
    development: {
      host: 'localhost',
      port: 8545,
      network_id: '*', // eslint-disable-line camelcase
    },
  },

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

  // Configure your compilers
  compilers: {
    solc: {
      version: "0.5.10",    // 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: true,
          runs: 20000
        },
        evmVersion: "petersburg"
      }
    }
  }
}