chore: add multiple api example (#207)

* chore: add multiple api example
* chore: update README.md

example/multiple/main.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"github.com/gin-gonic/gin"
+	swaggerFiles "github.com/swaggo/files"
+	ginSwagger "github.com/swaggo/gin-swagger"
+	v1 "github.com/swaggo/gin-swagger/example/multiple/api/v1"
+	v2 "github.com/swaggo/gin-swagger/example/multiple/api/v2"
+	_ "github.com/swaggo/gin-swagger/example/multiple/docs"
+)
+
+func main() {
+	// New gin router
+	router := gin.New()
+
+	// Register api/v1 endpoints
+	v1.Register(router)
+	router.GET("/swagger/v1/*any", ginSwagger.WrapHandler(swaggerFiles.Handler, ginSwagger.InstanceName("v1")))
+
+	// Register api/v2 endpoints
+	v2.Register(router)
+	router.GET("/swagger/v2/*any", ginSwagger.WrapHandler(swaggerFiles.Handler, ginSwagger.InstanceName("v2")))
+
+	// Listen and Server in
+	_ = router.Run()
+}