Fix user agent

pkg/crawler/colly.go

@@ -312,10 +312,6 @@ func CreateColly(delayTime int, concurrency int, cache bool, timeout int,
 	c.IgnoreRobotsTxt = true
 	c.AllowURLRevisit = false
 
-	if userAgent != "" {
-		c.UserAgent = userAgent
-	}
-
 	err := c.Limit(
 		&colly.LimitRule{
 			Parallelism: concurrency,
@@ -345,6 +341,10 @@ func CreateColly(delayTime int, concurrency int, cache bool, timeout int,
 		c.UserAgent = GenerateRandomUserAgent()
 	}
 
+	if userAgent != "" {
+		c.UserAgent = userAgent
+	}
+
 	// Use a Proxy if needed
 	if proxy != "" {
 		err := c.SetProxy(proxy)