Add middleware

default.go

@@ -0,0 +1,18 @@
+package router
+
+import (
+	"fmt"
+)
+
+func defaultNotFoundHandler(c *Context) error {
+	return c.String(404, `not found`)
+}
+
+func defaultMethodNotAllowedHandler(c *Context) error {
+	return c.String(504, `method not allowed`)
+}
+
+func defaultErrorHandler(c *Context, err interface{}) {
+	fmt.Println(err)
+	c.String(500, `internal server error`)
+}