Get total number of students for a particular course from the database

### What do you want to see?

Add new feature :- Get total number of students for a particular course from the database.

The user inputs the course code, the number of students and the name of the students are retrieved from the database and\
returned.

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct

Start by locating the repository's database access and the existing course, student, and attendance entry points. Confirm how a course code is looked up and what output format is already used; done means returning the total and student names for the requested course, with the relevant behavior covered by the project's existing checks.

由索引模型根据 Issue 内容生成。