support multi-module (#4)

* add multimodule
* re-package modules

server/internal/router/handler/turn.go

@@ -0,0 +1,17 @@
+package handler
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+func TurnHandler(c *gin.Context, executor CommandExecutor) {
+	state, err := executor.GenerateTurn()
+
+	if errorResponse(c, err) {
+		return
+	}
+
+	c.JSON(http.StatusOK, state)
+}