update doc api

@@ -33,6 +33,7 @@
 {
 {
     "operationAccount": "xxx@b.cb",
     "operationAccount": "xxx@b.cb",
     "classSmallOrderId": 326,
     "classSmallOrderId": 326,
+    "grade": "GRADE_2_B",
     "classOpenTime": 1560528000000,
     "classOpenTime": 1560528000000,
     "scheduleList": [
     "scheduleList": [
         {
         {
@@ -180,5 +181,3 @@ public static class ScheduleDetail {
     "timeSlice": "S2030"
     "timeSlice": "S2030"
 }
 }
 ```
 ```
-
-> 如果`scheduleClassId`参数有值，该接口更新课程信息；如果`scheduleClassId`为null，则创建一节课；