Fix problems

...ap/tutorial/belajarbelajar/controller/BaseController.java

.../tutorial/belajarbelajar/controller/CourseController.java

...utorial/belajarbelajar/controller/PengajarController.java

.../java/apap/tutorial/belajarbelajar/model/CourseModel.java

...ava/apap/tutorial/belajarbelajar/model/PengajarModel.java

...pap/tutorial/belajarbelajar/model/PenyelenggaraModel.java

...ava/apap/tutorial/belajarbelajar/repository/CourseDb.java

...a/apap/tutorial/belajarbelajar/repository/PengajarDb.java

...p/tutorial/belajarbelajar/repository/PenyelenggaraDb.java

...a/apap/tutorial/belajarbelajar/service/CourseService.java

...ap/tutorial/belajarbelajar/service/CourseServiceImpl.java

...apap/tutorial/belajarbelajar/service/PengajarService.java

.../tutorial/belajarbelajar/service/PengajarServiceImpl.java

...rial/belajarbelajar/service/PenyelenggaraServiceImpl.java