admin: Use gin-gonic as router

admin/api/version.go

@@ -1,13 +1,15 @@
 package api
 
 import (
-	"github.com/julienschmidt/httprouter"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
 )
 
-func init() {
-	router.GET("/api/version", apiHandler(showVersion))
+func DeclareVersionRoutes(router *gin.RouterGroup) {
+	router.GET("/version", showVersion)
 }
 
-func showVersion(_ httprouter.Params, body []byte) (interface{}, error) {
-	return map[string]interface{}{"version": 1.0}, nil
+func showVersion(c *gin.Context) {
+	c.JSON(http.StatusOK, gin.H{"version": 1.0})
 }