Add example implementation

example/.gitignore

@@ -0,0 +1 @@
+example

example/main.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"github.com/writeas/go-nodeinfo"
+	"net/http"
+)
+
+func main() {
+	cfg := nodeinfo.Config{
+		BaseURL: "http://localhost:8080",
+		InfoURL: "/api/nodeinfo",
+
+		Metadata: nodeinfo.Metadata{
+			NodeName:        "Agora",
+			NodeDescription: "A federated something-something.",
+			Private:         false,
+		},
+		Protocols: []nodeinfo.NodeProtocol{
+			nodeinfo.ProtocolActivityPub,
+		},
+		Services: nodeinfo.Services{
+			Inbound: []nodeinfo.NodeService{},
+			Outbound: []nodeinfo.NodeService{
+				nodeinfo.ServiceTwitter,
+				nodeinfo.ServiceTumblr,
+			},
+		},
+		Software: nodeinfo.SoftwareInfo{
+			Name:    "Agora",
+			Version: "1.0",
+		},
+	}
+	ni := nodeinfo.NewService(cfg, nodeInfoResolver{})
+
+	http.Handle(nodeinfo.NodeInfoPath, http.HandlerFunc(ni.NodeInfoDiscover))
+	http.Handle(cfg.InfoURL, http.HandlerFunc(ni.NodeInfo))
+
+	http.ListenAndServe(":8080", nil)
+}
+
+type nodeInfoResolver struct{}
+
+func (r nodeInfoResolver) IsOpenRegistration() (bool, error) {
+	return true, nil
+}
+
+func (r nodeInfoResolver) Usage() (nodeinfo.Usage, error) {
+	u := nodeinfo.Usage{
+		Users: nodeinfo.UsageUsers{
+			Total: 1,
+		},
+		LocalPosts: 1,
+	}
+	return u, nil
+}