created donations module

[Nabeelahh]

closes #76

Description
This PR sets up the donations module and defines the database schema for tracking contributions.
Key changes include:

• Generated donations module (nest g module donations).
• Created donations table schema with fields:
  • id (primary key)
  • project_id (foreign key → projects table)
  • donor_id (foreign key → users table)
  • amount (numeric donation value)
  • asset_type (currency/token type)
  • transaction_hash (unique identifier for transaction).
• Established relations to projects and users.
• Added indexes on transaction_hash (unique) and project_id for query optimization.
• Ran migration to apply schema changes.

This ensures donations are securely tracked, linked to projects and users, and optimized for performance.
Type of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Test addition/improvement

Checklist
-] I have run npm run build successfully with no errors

• I have run npm test and all tests pass
• If I added new test files, they all pass
• My code follows the project's style guidelines
• I have performed a self-review of my code

The following checks will run automatically on this PR:

1. Build Check - Ensures the project builds successfully
2. Test Check - Ensures all tests pass (including any new test files)

closes #76