public function store(Request $request)
{
    $inputs = $request->all();
    $this->validate($request,[
            'course_code'=>'required'
        ]);
    $batch = $request->batch;
    $students = User::select('student_id')->where('batch', $batch)->get();

    $course_codes = $inputs['course_code'];
    $data=[];
    foreach ($students as $student) {
        foreach ($course_codes as $course_code) {
        $data[]=[
            'batch' => $batch,
            'student_id' => $student->student_id,
            'semester' => $inputs['semester'],
            'course_code' => $course_code,
            "created_at" =>  CarbonCarbon::now(), # Datetime()
            "updated_at" => CarbonCarbon::now()  # Datetime()
            ];
        }
    }

    DB::table('assign_batches')->insert($data);
    return redirect('/admin/assign/batch/create')->with('message', 'A batch has been assigned to courses successfully!');
}