registry: Support the created_at field

Registries now have creation times.

registry.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"fmt"
 	"net/http"
+	"time"
 )
 
 const (
@@ -41,7 +42,8 @@ type RegistryDockerCredentialsRequest struct {
 
 // Registry represents a registry.
 type Registry struct {
-	Name string `json:"name,omitempty"`
+	Name      string    `json:"name,omitempty"`
+	CreatedAt time.Time `json:"created_at,omitempty"`
 }
 
 type registryRoot struct {

registry_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net/http"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/require"
 )
@@ -13,8 +14,11 @@ func TestRegistry_Create(t *testing.T) {
 	setup()
 	defer teardown()
 
+	createdAt, err := time.Parse(time.RFC3339, "2020-01-24T20:24:31Z")
+	require.NoError(t, err)
 	want := &Registry{
-		Name: "foo",
+		Name:      "foo",
+		CreatedAt: createdAt,
 	}
 
 	createRequest := &RegistryCreateRequest{
@@ -24,7 +28,8 @@ func TestRegistry_Create(t *testing.T) {
 	createResponseJSON := `
 {
 	"registry": {
-		"name": "foo"
+		"name": "foo",
+        "created_at": "2020-01-24T20:24:31Z"
 	}
 }`