add initial contribution.md

Signed-off-by: Thomas Kooi <thomas@thalassa.cloud>

Author: thojkooi

CONTRIBUTING.md

@@ -0,0 +1,247 @@
+# Contributing to Thalassa Cloud CLI
+
+Thank you for your interest in contributing to the Thalassa Cloud CLI! This document provides guidelines and instructions for contributing to the project.
+
+## Table of Contents
+
+- [Getting Started](#getting-started)
+- [Development Setup](#development-setup)
+- [Project Structure](#project-structure)
+- [Development Workflow](#development-workflow)
+- [Code Style and Conventions](#code-style-and-conventions)
+- [Testing](#testing)
+- [Commit Messages](#commit-messages)
+
+## Getting Started
+
+1. **Fork the repository** on GitHub
+2. **Clone your fork** locally:
+   ```bash
+   git clone https://github.com/YOUR_USERNAME/cli.git
+   cd cli
+   ```
+3. **Add the upstream remote**:
+   ```bash
+   git remote add upstream https://github.com/thalassa-cloud/cli.git
+   ```
+
+## Development Setup
+
+### Prerequisites
+
+- **Go 1.24 or later** - [Install Go](https://golang.org/doc/install)
+- **Make** - Usually pre-installed on Unix systems
+- **Git** - For version control
+
+### Building the Project
+
+```bash
+# Build the binary
+make build
+
+# The binary will be available at ./bin/tcloud
+./bin/tcloud --help
+```
+
+### Running Tests
+
+```bash
+# Run unit tests
+make test
+
+# Run E2E tests (requires configuration)
+# NOTE: Creates real resources, which may cost money
+make test-e2e
+```
+
+See the [Testing](#testing) section for more details.
+
+## Project Structure
+
+```
+cli/
+├── cmd/              # CLI commands organized by feature
+│   ├── context/      # Context management commands
+│   ├── iaas/         # IaaS-related commands
+│   ├── kubernetes/   # Kubernetes commands
+│   └── ...
+├── internal/         # Internal packages (not exported)
+│   ├── config/       # Configuration management
+│   ├── table/        # Table formatting utilities
+│   └── ...
+├── e2e/              # End-to-end tests
+├── docs/             # Documentation
+└── main.go          # Application entry point
+```
+
+### Command Organization
+
+Commands are organized in the `cmd/` directory following this structure:
+- Each top-level command has its own package (e.g., `cmd/kubernetes/`)
+- Subcommands are in the same package or subdirectories
+- Command files follow naming conventions:
+  - `{command}.go` - Main command definition
+  - `{subcommand}.go` - Subcommand implementation
+
+## Development Workflow
+
+1. **Create a feature branch**:
+   ```bash
+   git checkout -b feature/your-feature-name
+   ```
+
+2. **Make your changes** following the code style guidelines
+
+3. **Write tests** for your changes (see [Testing](#testing))
+
+4. **Run tests** to ensure everything passes:
+   ```bash
+   make test
+   ```
+
+5. **Commit your changes** using semantic commit messages (see [Commit Messages](#commit-messages))
+
+6. **Push to your fork**:
+   ```bash
+   git push origin feature/your-feature-name
+   ```
+
+7. **Create a Pull Request** on GitHub
+
+## Code Style and Conventions
+
+### Go Code Style
+
+- Follow standard Go formatting: `go fmt ./...`
+- Follow [Effective Go](https://golang.org/doc/effective_go) guidelines
+- Use `golangci-lint` or similar tools for linting (if configured)
+
+## Testing
+
+### Unit Tests
+
+Unit tests are located alongside the code they test (e.g., `labels_test.go` in the `labels` package).
+
+- Use table-driven tests for multiple test cases
+- Use the `testify` package for assertions
+- Keep tests simple and focused on one behavior
+
+**Example:**
+```go
+func TestParseLabelSelector(t *testing.T) {
+    tests := []struct {
+        name     string
+        selector string
+        expected map[string]string
+    }{
+        {
+            name:     "single label",
+            selector: "key1=value1",
+            expected: map[string]string{"key1": "value1"},
+        },
+        // ... more test cases
+    }
+
+    for _, tt := range tests {
+        t.Run(tt.name, func(t *testing.T) {
+            result := ParseLabelSelector(tt.selector)
+            assert.Equal(t, tt.expected, result)
+        })
+    }
+}
+```
+
+**Running Unit Tests:**
+```bash
+# Run all unit tests
+make test
+
+# Run tests for a specific package
+go test ./internal/labels/...
+
+# Run tests with verbose output
+go test -v ./internal/labels/...
+```
+
+### E2E Tests
+
+End-to-end tests are located in the `e2e/` directory and test the actual CLI binary against a real API.
+
+**Setup:**
+1. Build the binary: `make build`
+2. Configure environment variables (see `e2e/README.md` for details):
+   ```bash
+   export TCLOUD_E2E_API_ENDPOINT="https://api.thalassa.cloud"
+   export TCLOUD_E2E_PERSONAL_ACCESS_TOKEN="your-token"
+   ```
+
+**Running E2E Tests:**
+```bash
+# Run all E2E tests
+make test-e2e
+
+# Run specific E2E test
+go test ./e2e/... -v -run TestVersion
+
+# Run with custom binary path
+TCLOUD_E2E_BINARY_PATH=/path/to/tcloud go test ./e2e/... -v
+```
+
+For more details, see `e2e/README.md`.
+
+## Commit Messages
+
+We follow **semantic commit message** conventions. Commit messages should be clear, descriptive, and follow this format:
+
+```
+<type>(<scope>): <subject>
+
+<body>
+
+<footer>
+```
+
+### Types
+
+- `feat`: New feature
+- `fix`: Bug fix
+- `docs`: Documentation changes
+- `test`: Adding or updating tests
+- `refactor`: Code refactoring (no behavior change)
+- `style`: Code style changes (formatting, etc.)
+- `chore`: Maintenance tasks
+- `perf`: Performance improvements
+
+### Examples
+
+```
+feat(vpcs): add support for label selectors in list command
+
+This allows users to filter VPCs by labels when listing them,
+improving usability for managing large numbers of resources.
+
+Closes #123
+```
+
+```
+fix(auth): handle expired tokens gracefully
+
+Previously, expired tokens would cause a panic. Now they are
+handled with a clear error message prompting the user to re-authenticate.
+```
+
+```
+test(e2e): add E2E tests for me organisations command
+
+Adds comprehensive E2E tests covering all flags and output formats
+for the me organisations command.
+```
+
+### Guidelines
+
+- Use imperative mood ("add" not "added" or "adds")
+- Keep the subject line under 50 characters
+- Capitalize the first letter of the subject
+- Don't end the subject with a period
+- Use the body to explain *what* and *why* (not *how*)
+- Reference issues and PRs in the footer