diff --git a/spike/review/reinvent/ezmded/server/tree.go b/spike/review/reinvent/ezmded/server/tree.go
new file mode 100644
index 0000000..2b93d9b
--- /dev/null
+++ b/spike/review/reinvent/ezmded/server/tree.go
@@ -0,0 +1,79 @@
+package main
+
+import (
+	"errors"
+	"io/ioutil"
+	"os"
+	"time"
+
+	yaml "gopkg.in/yaml.v2"
+)
+
+type Tree struct {
+	path string
+}
+
+type Branch struct {
+	Title   string
+	Deleted bool
+	Updated time.Time
+	PID     string
+}
+
+func NewTree(path string) *Tree {
+	return &Tree{
+		path: path,
+	}
+}
+
+func (tree *Tree) Get() (map[string]Branch, error) {
+	b, err := ioutil.ReadFile(tree.path)
+	if os.IsNotExist(err) {
+		return map[string]Branch{}, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	var m map[string]Branch
+	err = yaml.Unmarshal(b, &m)
+	return m, err
+}
+
+func (tree *Tree) Set(m map[string]Branch) error {
+	b, err := yaml.Marshal(m)
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(tree.path, b, os.ModePerm)
+}
+
+func (tree *Tree) Del(id string) error {
+	m, err := tree.Get()
+	if err != nil {
+		return err
+	}
+	branch, ok := m[id]
+	if !ok {
+		return nil
+	}
+	branch.Updated = time.Now().UTC()
+	branch.Deleted = true
+	m[id] = branch
+	return tree.Set(m)
+}
+
+func (tree *Tree) Put(id string, branch Branch) error {
+	branch.Updated = time.Now().UTC()
+	if branch.Title == "" {
+		branch.Title = "Untitled (" + time.Now().UTC().String() + ")"
+	}
+	m, err := tree.Get()
+	if err != nil {
+		return err
+	}
+	if _, ok := m[branch.PID]; !ok && branch.PID != "" {
+		return errors.New("PID does not exist")
+	}
+	m[id] = branch
+	return tree.Set(m)
+}
diff --git a/spike/review/reinvent/ezmded/server/tree_test.go b/spike/review/reinvent/ezmded/server/tree_test.go
new file mode 100644
index 0000000..d509b42
--- /dev/null
+++ b/spike/review/reinvent/ezmded/server/tree_test.go
@@ -0,0 +1,54 @@
+package main
+
+import (
+	"path"
+	"testing"
+	"time"
+)
+
+func TestTree(t *testing.T) {
+	path := path.Join(t.TempDir(), "index.yaml")
+	tree := NewTree(path)
+
+	if m, err := tree.Get(); err != nil {
+		t.Fatal(err)
+	} else if m == nil {
+		t.Fatal(m)
+	}
+
+	if err := tree.Del("id"); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := tree.Put("id", Branch{PID: "fake"}); err == nil {
+		t.Fatal(err)
+	}
+
+	if err := tree.Put("id", Branch{}); err != nil {
+		t.Fatal(err)
+	} else if branches, err := tree.Get(); err != nil {
+		t.Fatal(err)
+	} else if branch, ok := branches["id"]; !ok {
+		t.Fatal(err)
+	} else if branch.Title == "" {
+		t.Fatal(branch)
+	} else if time.Since(branch.Updated) > time.Hour {
+		t.Fatal(branch)
+	} else if branch.Deleted {
+		t.Fatal(branch)
+	}
+
+	if err := tree.Put("id2", Branch{PID: "id"}); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := tree.Del("id"); err != nil {
+		t.Fatal(err)
+	} else if branches, err := tree.Get(); err != nil {
+		t.Fatal(err)
+	} else if branch, ok := branches["id"]; !ok {
+		t.Fatal(ok)
+	} else if !branch.Deleted {
+		t.Fatal(branch)
+	}
+}