增加获取学生、乐团对应的年级列表

mec-student/src/main/java/com/ym/mec/student/controller/MusicGroupController.java

@@ -345,7 +345,7 @@ public class MusicGroupController extends BaseController {
     @ApiOperation(value = "获取乐团的年级列表")
     @GetMapping("/getGradeList")
     @ApiImplicitParams({@ApiImplicitParam(name = "musicGroupId", value = "乐团编号", required = true, dataType = "String")})
-    public HttpResponseResult getGradeList(String musicGroupId) {
+    public HttpResponseResult<Map<Integer,String>> getGradeList(String musicGroupId) {
         MusicGroup musicGroup = musicGroupService.get(musicGroupId);
         return succeed(organizationService.getGradeList(musicGroup.getOrganId()));
     }