[30] Develop GitHub integration for participant assignment submissions

[daaimah123]

Problem: We need to allow participants to submit their work using GitHub links and track these submissions.

Implementation Details:

1. Design a database schema for storing GitHub submission links
2. Develop an interface for participants to submit GitHub links for assignments
3. Implement GitHub API integration to verify repository ownership and access
4. Create a system for tracking submission status (submitted, reviewed, etc.)
5. Develop an admin interface for viewing and managing GitHub submissions
6. Implement a webhook system to track changes in submitted repositories
7. Create a feature to allow downloading submission data to a spreadsheet

Technical Concepts:

• GitHub API integration
• Webhook implementation
• Spreadsheet generation (e.g., using libraries like xlsx)

Dependencies: Issues 17, 28

Acceptance Criteria:

• Participants can easily submit GitHub links for their assignments
• System verifies repository ownership and access before accepting submissions
• Admins can view all submissions, their status, and associated GitHub data
• Webhook system tracks and reports relevant changes in submitted repositories
• Admins can download submission data to a spreadsheet format
• Integration with GitHub doesn't compromise system security