Add CONTRIBUTING.md to guide contributors

[kmuwanga83]

📌 Problem

There is no clear guideline for how developers should contribute to the project.

🎯 Objective

Create a CONTRIBUTING.md file to standardize contributions.

✅ Tasks

• Add steps for:
  • Forking the repo
  • Creating branches
  • Writing commit messages
  • Submitting pull requests
• Include coding standards
• Add issue reporting guidelines

🧪 Acceptance Criteria

• CONTRIBUTING.md exists in root directory
• README links to it
• New contributors can follow the workflow easily

💡 Suggested Labels

documentation, community, good first issue