Fix

app/Http/Controllers/StudentController.php

app/Models/Student.php

app/Models/Subject.php

...se/migrations/2021_02_16_101240_create_students_table.php

database/migrations/2021_02_16_101907_create_marks_table.php

resources/views/groups/edit.blade.php

resources/views/groups/index.blade.php

resources/views/groups/show.blade.php

resources/views/students/edit.blade.php

resources/views/students/filter.blade.php

resources/views/students/index.blade.php

resources/views/students/profile.blade.php

resources/views/students/show.blade.php

resources/views/subjects/edit.blade.php

resources/views/subjects/index.blade.php

resources/views/subjects/show.blade.php

routes/web.php