chore: add README.md

Author: nnnkkk7

README.md

@@ -1 +1,148 @@
-# openfeature-go-server-sdk
+# Bucketeer - OpenFeature Go server provider
+
+This is the official Go OpenFeature provider for accessing your feature flags with [Bucketeer](https://bucketeer.io/).
+
+[Bucketeer](https://bucketeer.io) is an open-source platform created by [CyberAgent](https://www.cyberagent.co.jp/en/) to help teams make better decisions, reduce deployment lead time and release risk through feature flags. Bucketeer offers advanced features like dark launches and staged rollouts that perform limited releases based on user attributes, devices, and other segments.
+
+In conjunction with the [OpenFeature SDK](https://openfeature.dev/docs/reference/concepts/provider) you will be able to evaluate your feature flags in your **server-side** applications.
+
+> [!WARNING]
+> This is a beta version. Breaking changes may be introduced before general release.
+
+For documentation related to flags management in Bucketeer, refer to the [Bucketeer documentation website](https://docs.bucketeer.io/sdk/server-side/go).
+
+## Supported Go versions
+
+Minimum requirements:
+
+| Tool | Version |
+| ----- | ------- |
+| Go    | 1.21+   |
+
+## Installation
+
+```bash
+go get github.com/bucketeer-io/openfeature-go-server-sdk
+```
+
+## Usage
+
+### Initialize the provider
+
+Bucketeer provider needs to be created and then set in the global OpenFeatureAPI.
+
+```go
+import (
+	"context"
+	"github.com/bucketeer-io/go-server-sdk/pkg/bucketeer"
+	"github.com/bucketeer-io/openfeature-go-server-sdk/pkg/provider"
+	"github.com/open-feature/go-sdk/openfeature"
+)
+
+func main() {
+	// SDK configuration
+	options := []bucketeer.Option{
+		bucketeer.WithAPI(
+			"YOUR_API_KEY",
+			"YOUR_API_ENDPOINT",
+		),
+		bucketeer.WithTag("YOUR_FEATURE_TAG"),
+		// Add other options as needed
+	}
+
+	// Create provider
+	p, err := provider.NewProvider(options)
+	if err != nil {
+		// Error handling
+	}
+
+	// User configuration
+	userID := "targetingUserId"
+	ctx := openfeature.NewEvaluationContext(
+		userID,
+		map[string]interface{}{
+			// User attributes are optional
+		},
+	)
+
+	// Set context before setting provider
+	openfeature.SetEvaluationContext(ctx)
+	openfeature.SetProvider(p)
+}
+```
+
+See our [documentation](https://docs.bucketeer.io/sdk/server-side/go) for more SDK configuration.
+
+The evaluation context allows the client to specify contextual data that Bucketeer uses to evaluate the feature flags.
+
+The `targetingKey` is the user ID (Unique ID) and cannot be empty.
+
+### Update the Evaluation Context
+
+You can update the evaluation context with the new attributes if the user attributes change.
+
+```go
+ctx := openfeature.NewEvaluationContext(
+	userID,
+	map[string]interface{}{
+		"buyer": "true",
+	},
+)
+openfeature.SetEvaluationContext(ctx)
+```
+
+
+## Example
+
+Check out the [example directory](./example) for a complete working example of how to use this SDK in a web application.
+
+
+## Testing
+
+### Unit Tests
+
+To run unit tests:
+
+```bash
+make test
+```
+
+### E2E Tests
+
+The E2E tests can run in two modes:
+
+
+```bash
+export API_KEY="YOUR_API_KEY"
+export HOST="YOUR_API_ENDPOINT"
+export PORT="443"
+export TAG="YOUR_FEATURE_TAG" # optional
+
+# You can also specify flag IDs (optional)
+export BOOLEAN_FLAG_ID="your-boolean-flag-id"
+export STRING_FLAG_ID="your-string-flag-id"
+export INT_FLAG_ID="your-int-flag-id"
+export FLOAT_FLAG_ID="your-float-flag-id"
+export OBJECT_FLAG_ID="your-object-flag-id"
+
+make e2e
+```
+
+2. **With mock provider** - No credentials needed:
+
+```bash
+# Will automatically use a mock provider
+make e2e
+```
+
+For more details, see the [E2E Test README](./test/e2e/README.md).
+
+## Contributing
+
+We would ❤️ for you to contribute to Bucketeer and help improve it! Anyone can use and enjoy it!
+
+Please follow our contribution guide [here](https://docs.bucketeer.io/contribution-guide/).
+
+## License
+
+Apache License 2.0, see [LICENSE](https://github.com/bucketeer-io/openfeature-go-server-sdk/blob/main/LICENSE).