componentDidMount() {
         window.addEventListener('load', function() {

         // Checking if Web3 has been injected by the browser (Mist/MetaMask)
            if (typeof web3 !== 'undefined') {
                 // Use Mist/MetaMask's provider
                 window.web3 = new Web3(web3.currentProvider);
             } else {
                 console.log('No web3? You should consider trying MetaMask!')
                 // fallback - use your fallback strategy (local node / hosted node + in-dapp id mgmt / fail)
                 window.web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));
         }
         })
    }