support multi-module (#4)

* add multimodule
* re-package modules

model/rest/init.go

@@ -0,0 +1,9 @@
+package rest
+
+type Init struct {
+	Races []Race `json:"races" binding:"required,gte=10"`
+}
+
+type Race struct {
+	Name string `json:"name" binding:"required,notblank"`
+}