update README.md with quick start and release date. (#157)

README.md

@@ -6,13 +6,105 @@
 
 The Go [OpenTelemetry](https://opentelemetry.io/) client.
 
+## Installation
+
+This repository includes multiple packages. The `api`
+package contains core data types, interfaces and no-op implementations that comprise the OpenTelemetry API following
+[the
+specification](https://github.com/open-telemetry/opentelemetry-specification).
+The `sdk` package is the reference implementation of the API.
+
+Libraries that produce telemetry data should only depend on `api`,
+and defer the choice of the SDK to the application developer. Applications may
+depend on `sdk` or another package that implements the API. 
+
+To install the API and SDK packages,
+
+```
+$ go get -u go.opentelemetry.io
+```
+
+## Quick Start
+
+```go
+package main
+
+import (
+	"context"
+	"log"
+
+	apitrace "go.opentelemetry.io/api/trace"
+	"go.opentelemetry.io/exporter/trace/stdout"
+	sdktrace "go.opentelemetry.io/sdk/trace"
+)
+
+func initTracer() {
+	sdktrace.Register()
+
+	exporter, err := stdout.NewExporter(stdout.Options{PrettyPrint: true})
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	ssp := sdktrace.NewSimpleSpanProcessor(exporter)
+	sdktrace.RegisterSpanProcessor(ssp)
+
+	// For the demonstration, use sdktrace.AlwaysSample sampler to sample all traces.
+	// In a production application, use sdktrace.ProbabilitySampler with a desired probability.
+	sdktrace.ApplyConfig(sdktrace.Config{DefaultSampler: sdktrace.AlwaysSample()})
+}
+
+func main() {
+	initTracer()
+
+	apitrace.GlobalTracer().WithSpan(context.Background(), "foo",
+		func(ctx context.Context) error {
+			apitrace.GlobalTracer().WithSpan(ctx, "bar",
+				func(ctx context.Context) error {
+					apitrace.GlobalTracer().WithSpan(ctx, "baz",
+						func(ctx context.Context) error {
+							return nil
+						},
+					)
+					return nil
+				},
+			)
+			return nil
+		},
+	)
+}
+
+```
+
+See the [API
+documentation](https://go.opentelemetry.io/) for more
+detail, and the
+[opentelemetry-example-app](./example/README.md)
+for a complete example.
+
 ## Contributing
 
 See the [contributing file](CONTRIBUTING.md).
 
-## TODO
+## Release Schedule
 
-TODO
+OpenTelemetry Go is under active development. Below is the release schedule
+for the Go library. The first version of release isn't guaranteed to conform
+to a specific version of the specification, and future releases will not
+attempt to maintain backwards compatibility with the alpha release.
+
+| Component                   | Version | Target Date     |
+| --------------------------- | ------- | --------------- |
+| Tracing API                 | Alpha   | October 4 2019  |
+| Tracing SDK                 | Alpha   | October 4 2019  |
+| Metrics API                 | Alpha   | October 14 2019 |
+| Metrics SDK                 | Alpha   | October 14 2019 |
+| Zipkin Trace Exporter       | Alpha   | Unknown         |
+| Jaeger Trace Exporter       | Alpha   | October 4 2019  |
+| Prometheus Metrics Exporter | Alpha   | October 14 2019 |
+| Trace Context Propagation   | Alpha   | Unknown         |
+| OpenTracing Bridge          | Alpha   | October         |
+| OpenCensus Bridge           | Alpha   | Unknown         |
 
 ## Experimental streaming SDK