message: API: checkPrivileges of /api/export/course/:id
diff: -import {Authorized, CurrentUser, Get, JsonController, Param, UseBefore} from 'routing-controllers';
  +import {Authorized, CurrentUser, Get, JsonController, Param, UseBefore, ForbiddenError} from 'routing-controllers';
  import passportJwtMiddleware from '../security/passportJwtMiddleware';
  import {Course} from '../models/Course';
  import {Lecture} from '../models/Lecture';
  @@ -41,8 +41,11 @@ export class ExportController {
  * }
  */
  @Get('/course/:id')
  - async exportCourse(@Param('id') id: string) {
  + async exportCourse(@Param('id') id: string, @CurrentUser() currentUser: IUser) {
  const course = await Course.findById(id);
  + if (!course.checkPrivileges(currentUser).userCanEditCourse) {
  + throw new ForbiddenError();
  + }
  return course.exportJSON();
  }
  