message: API: Secure and refactor getLecture route
diff: @@ -32,9 +32,13 @@ export class LectureController {
  * }
  */
  @Get('/:id')
  - getLecture(@Param('id') id: string) {
  - return Lecture.findById(id)
  - .then((l) => l.toObject());
  + async getLecture(@Param('id') id: string, @CurrentUser() currentUser: IUser) {
  + const course = await Course.findOne({lectures: id});
  + if (!course.checkPrivileges(currentUser).userCanViewCourse) {
  + throw new ForbiddenError();
  + }
  + const lecture = await Lecture.findById(id);
  + return lecture.toObject();
  }
  /**
  