chore: add multiple api example (#207)

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

example/multiple/api/v2/example.go

@@ -0,0 +1,26 @@
+package v2
+
+import (
+	"github.com/gin-gonic/gin"
+)
+
+type Book struct {
+	ID     int     `json:"id,omitempty"`
+	Title  string  `json:"title"`
+	Author string  `json:"author"`
+	Year   *uint16 `json:"year"`
+}
+
+//
+// @Summary Get a list of books in the the store
+// @Description get string by ID
+// @Accept  json
+// @Produce  json
+// @Success 200 {array} Book "ok"
+// @Router /books [get]
+func GetBooks(ctx *gin.Context) {
+	ctx.JSON(200, []Book{
+		{ID: 1, Title: "Book 3", Author: "Author 3", Year: nil},
+		{ID: 2, Title: "Book 4", Author: "Author 4", Year: nil},
+	})
+}