message: API: Remove unused CourseController route parameters
diff: -import {Request} from 'express';
  import {
  Authorized, BadRequestError,
  Body,
  @@ -8,7 +7,6 @@ import {
  Param,
  Post,
  Put,
  - Req,
  UploadedFile,
  UseBefore
  } from 'routing-controllers';
  @@ -424,7 +422,7 @@ export class CourseController {
  */
  @Authorized(['teacher', 'admin'])
  @Post('/')
  - async addCourse(@Body() course: ICourse, @Req() request: Request, @CurrentUser() currentUser: IUser) {
  + async addCourse(@Body() course: ICourse, @CurrentUser() currentUser: IUser) {
  // Note that this might technically have a race condition, but it should never matter because the new course ids remain unique.
  // If a strict version is deemed important, see mongoose Model.findOneAndUpdate for a potential approach.
  const existingCourse = await Course.findOne({name: course.name});
  @@ -543,7 +541,7 @@ export class CourseController {
  */
  @Authorized(['student'])
  @Post('/:id/leave')
  - async leaveStudent(@Param('id') id: string, @Body() data: any, @CurrentUser() currentUser: IUser) {
  + async leaveStudent(@Param('id') id: string, @CurrentUser() currentUser: IUser) {
  const course = await Course.findById(id);
  if (!course) {
  throw new NotFoundError();
  