Add employee database and CRUD API endpoints

[Lekhaaa-S]

What this does

Adds an Employee model with 4 API endpoints and an admin view for viewing saved data.

APIs

• POST /employees/api/add/ — add new employee
• GET /employees/api/<emp_id>/ — get employee by emp_id
• DELETE /employees/api/<emp_id>/delete/ — delete employee by id
• PUT /employees/api/<emp_id>/salary/ — update employee salary

Admin view

Employee model registered in Django admin (/admin/) to view saved data.

Testing

Verified all 4 endpoints with curl and confirmed correct behavior:

• Add: creates employee, returns 201 with employee data
• Get: returns employee by emp_id, 404 if not found
• Update salary: updates and returns updated employee
• Delete: removes employee, confirmed 404 on subsequent get

Also verified in browser via Django admin panel at /admin/.