Fixed #5 metamask breaking changes

https://medium.com/metamask/https-medium-com-metamask-breaking-change-injecting-web3-7722797916a8

Author: bestony

assets/payments.js

@@ -1,9 +1,20 @@
 function requestPayment(token) {
-if (typeof web3 !== 'undefined') {
+if (window.ethereum){
+ window.web3 = new Web3(ethereum);
+ try {
+ ethereum.enable();
+ } catch (error) {
+ console.log(error)
+ }
+
+}else if (window.web3){
 web3 = new Web3(web3.currentProvider);
-} else {
-alert("请先安装 Metamask !");
 }
+else {
+ alert("Please Install Metamask at First！")
+ return ;
+ }
+
 var xmlhttp;
 var formData = new FormData();
 if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari