create and move middlewares to seperate folder

web/middleware/domainValidator.go

@@ -0,0 +1,21 @@
+package middleware
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+)
+
+func DomainValidatorMiddleware(domain string) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		host := strings.Split(c.Request.Host, ":")[0]
+
+		if host != domain {
+			c.AbortWithStatus(http.StatusForbidden)
+			return
+		}
+
+		c.Next()
+	}
+}