add smallclass.md

+## 创建群组接口
+
+>小班授课建群
+>
+
+接口地址: /teaching/smallclass/group
+
+Request method：POST
+
+Request body:
+
+```
+{
+    "smallClassId": 123,
+    "teacherId": [
+        111,
+        222,
+        333
+    ],
+    "studentId": [
+        444,
+        555,
+        666
+    ]
+}
+```
+
+Response:
+
+```
+{
+    "data": {
+        "groupId": "@TGP#demo",
+        "chatRoomId": 2231445
+    },
+    "returnCode": 200,
+    "returnMsg": "success"
+}
+```
+
+## 获取群组接口
+
+>小班授课获取群房间信息
+>
+
+接口地址: /teaching/smallclass/group
+
+Request method：GET
+
+Request Params：
+
+|参数名         |是否必须    |说明     |参数类型          |
+|--------------|-----------|--------|-----------------|
+|small_class_id|是         |小班id   |Long             |
+
+response:
+
+```
+{
+    "data": {
+        "groupId": "@TGP#demo",
+        "chatRoomId": 2231445
+    },
+    "returnCode": 200,
+    "returnMsg": "success"
+}
+```
+
+## 解散群组接口
+
+>小班授课解散群房间信息
+>
+
+接口地址: /teaching/smallclass/group
+
+Request method：DELETE
+
+Request Params：
+
+|参数名         |是否必须    |说明     |参数类型          |
+|--------------|-----------|--------|-----------------|
+|small_class_id|是         |小班id   |Long             |
+
+response:
+
+```
+
+{
+    "data": "",
+    "returnCode": 200,
+    "returnMsg": "success"
+}
+```
+
+
+## 公开课加积分接口
+
+>1.公开课加积分接口,目前是加300分
+>2.此接口需要access_token
+>
+>3.class_type:
+>正常课,NORMAL
+>小班课,SMALL
+>公开课,PUBLIC
+>
+>目前只能传 PUBLIC
+
+接口地址: /teaching/student/score/constant
+
+Request method：POST
+
+Request Params：
+
+|参数名         |是否必须    |说明             |参数类型          |
+|--------------|-----------|----------------|-----------------|
+|lesson_id     |是         |课程id           |String           |
+|user_id       |是         |需要加积分的用户id |Long             |
+|class_type    |是         |课程类型,见说明   |String            |
+
+
+response:
+
+```
+{
+  "data": {
+    "score": 300
+  },
+  "returnCode": 200,
+  "returnMsg": "success"
+}
+```