Desktop app dynamic config of API Port (#40)

* added dynamic configuration of Port in Desktop app
* added dynamic configuration of API_URL to docker deployments.

Now it works with editing only .env file.

backend/router/setup.go

@@ -32,7 +32,7 @@ func SetupGin(r *gin.Engine) {
 		}
 		corsConfig = cors.Config{
 			AllowOrigins:     allowedOrigins,
-			AllowMethods:     []string{"GET", "POST", "PUT", "PATCH", "DELETE"},
+			AllowMethods:     []string{"GET", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"},
 			AllowHeaders:     []string{"Origin", "Content-Type", "Authorization"},
 			ExposeHeaders:    []string{"Content-Length"},
 			AllowCredentials: true,