add docs/app-payment-stripe.md.

docs/app-payment-stripe.md

+#### 申请开通Stripe
+1. [登录/注册](https://dashboard.stripe.com/login)
+
+2. 进入主页后，点击顶部继续按钮，完善公司信息
+![](https://partner-dcloud-native.oss-cn-hangzhou.aliyuncs.com/images/uniapp/payment/stripe_home_page.png)
+
+3. 完善信息
+![](https://partner-dcloud-native.oss-cn-hangzhou.aliyuncs.com/images/uniapp/payment/stripe_company_info.png)
+
+4. 完善公司信息后，回到首页即可在右侧查看密钥
+![](https://partner-dcloud-native.oss-cn-hangzhou.aliyuncs.com/images/uniapp/payment/stripe_get_publishkey.png)
+
+------
+
+#### 使用Stripe支付
+1. 在manifest.json文件“App模块配置”项的“Payment(支付)”下，勾选“stripe支付”项并配置returnURL(只需配置iOS),格式为'your-app://stripe'(示例 hbuilder://stripe)
+![](https://partner-dcloud-native.oss-cn-hangzhou.aliyuncs.com/images/uniapp/payment/stripe_setup_manifest_info.jpg)
+
+   相关参考:[配置一个自定义页面内跳转协议 (URL Scheme)](https://ask.dcloud.net.cn/article/64)
+2. 服务器生成支付订单[参考stripeAPI](https://stripe.com/docs/payments/accept-a-payment)
+    ``` js
+    uni.request({
+      url: 'https://stripe-mobile-payment-sheet.glitch.me/checkout',//仅为示例
+      method: "POST", 
+      success:(res) => {
+        console.log("订单信息" + res.data);
+        var publishKey = res.data.publishableKey;
+        var paymentIntent = res.data.paymentIntent; 
+        var customer = res.data.customer;
+        var ephemeralKey = res.data.ephemeralKey;
+      }
+	 })
+    ```
+3. 应用中调用支付功能
+    
+| 参数名称    | 参数说明 | 必须 | 
+|-------------|-------|-----|
+| publishKey    | 公钥(获取方式详见stripe开通文档) | 是  |
+| paymentIntent     | 订单信息  | 是 | 
+| merchantName | 商户名称 |是 |
+| customer  | 如果要设置支付方式供以后使用，则必须将它绑定到一个 Customer | 否 |
+| ephemeralKey    | EphemeralKey的作用是让 SDK 临时访问 Customer   | 否 |
+| isAllowDelay    | 是否支持延迟支付,默认不支持(将 isAllowDelay 设置为 true 后可使用一些较慢的支付方式，例如 SEPA 借记和 Sofort 对于这些支付方式，只有当 PaymentSheet 完成后才能知道最终的付款状态是成功还是失败。如果您允许这样，则通知客户您已确认他们的订单，但收到付款后才能履行（例如，发货）订单。)   | 否 |
+
+注：customer与ephemeralKey必须成对出现，只传其一无效
+  * uni-app项目示例
+  ``` js
+  uni.getProvider({
+   service: 'payment',
+   success: function(res) {
+		console.log(res);
+      if (~res.provider.indexOf('stripe')) {
+      
+        uni.request({
+          url: 'https://stripe-mobile-payment-sheet.glitch.me/checkout',
+          method: "POST",
+          success: (res) => {
+            console.log(res.data);
+              uni.requestPayment({
+                "provider": "stripe",
+                "orderInfo": {
+                  "publishKey": res.data.publishableKey, //公钥
+                  "paymentIntent": res.data.paymentIntent, //订单信息
+                  "customer": res.data.customer, //支付方式等信息
+                  "ephemeralKey": res.data.ephemeralKey, //信息key
+                  "isAllowDelay": true, //是否支持延迟支付  默认false
+                  "merchantName": "数字天堂", //商户名
+                },
+                success(res) {
+                  console.log(res);
+                },
+                fail(e) {
+                  console.log(e);
+                }
+             });
+          }
+		});
+		}
+	}
+  });
+  ```
+
+  * 5+项目示例
+    ``` js
+    //获取渠道
+    var stripeSev = null;
+    plus.payment.getChannels(function(channels) {
+     for (var i in channels) {
+       var channel = channels[i];
+       if (channel.id === 'stripe') {
+        stripeSev = channel;
+       }
+	  }
+	}, function(e) {
+	  console.log("获取支付渠道失败：" + e.message);
+	});
+	//发起支付
+    var statement = {
+      "publishKey": publishKey, //公钥
+      "paymentIntent": paymentIntent,//订单加密信息
+      "merchantName":"数字天堂",//  
+      "customer":customer,
+      "ephemeralKey":ephemeralKey,//
+      "isAllowDelay":true,//
+    };
+    plus.payment.request(stripeSev, statement, function(result) {
+      console.log("支付成功");
+    }, function(e) {
+      console.log("支付失败：" + e.message);
+    });
+    ```
+