diff --git a/id.go b/id.go
new file mode 100644
index 0000000..4ebe2b3
--- /dev/null
+++ b/id.go
@@ -0,0 +1,9 @@
+package budgeteer
+
+// ID is an implementation of a UUID
+type ID [16]byte
+
+// IDGenerator generates new IDs
+type IDGenerator interface {
+	New() ID
+}
diff --git a/user.go b/user.go
index c099f95..e239545 100644
--- a/user.go
+++ b/user.go
@@ -2,7 +2,7 @@ package budgeteer
 
 // User struct contains Login information
 type User struct {
-	ID       int
+	ID       ID
 	Email    string
 	Password string
 	Name     string
@@ -10,8 +10,8 @@ type User struct {
 
 // UserService provides Methods for CRUD of Users
 type UserService interface {
-	User(id int) (*User, error)
+	User(id ID) (*User, error)
 	//Users() ([]*User, error)
-	//CreateUser(u *User) error
+	CreateUser(u *User) error
 	//DeleteUser(id int) error
 }