feat(ci): implement ci pipeline

[Bolu1]

CI Pipeline Implementation for DefiFundr Backend

Overview

This PR implements a continuous integration (CI) pipeline using GitHub Actions for the DefiFundr backend project. The pipeline automates code quality checks, testing, and build verification on all branches and pull requests.

Changes

• Added GitHub Actions workflow configuration in
• Configured linting with golangci-lint
• Set up automated testing with PostgreSQL integration
• Implemented build verification and artifact storage

Features

Linting

• Uses golangci-lint to check code quality and ensure consistent coding standards
• Configured with essential linters for Go projects
• Runs automatically on all branches and PRs

Testing

• Executes all unit and integration tests
• Sets up PostgreSQL service container for database-dependent tests
• Collects and reports code coverage
• Configures proper database connection for test environment

Build Verification

• Ensures the application builds successfully
• Creates and stores build artifacts for reference
• Runs after successful lint and test jobs

Documentation

• Added detailed documentation on the CI pipeline structure
• Included instructions for troubleshooting CI issues
• Provided guidelines for running CI checks locally

Related Issue

Closes #43

[demola234]

Please kindly review and make the changes
@Bolu1

[demola234]

check previous CI implementation. Use similar strategies, avoid exposing sensitive data in CI implementation

[demola234]

Use version of golang used in the project or upgrade project to current version

[demola234]

Postgres is used but migration test in ci is not done

[demola234]

reduce sensitivity of linter for now

[Bolu1]

Hi @demola234, i've made the requested changes can you take a look now