Fix jwt middleware

Signed-off-by: Asai Neko <sugar@sne.moe>

middleware/jwt.go

@@ -18,18 +18,12 @@ func JWTAuth(required bool) gin.HandlerFunc {
 			return
 		}
 
-		if required == true {
+		if required == true && uid == "" {
 			c.JSON(401, gin.H{"status": "unauthorized"})
 			c.Next()
 			return
 		}
 
-		if uid == "" {
-			c.Set("user_id", "")
-			c.Next()
-			return
-		}
-
 		c.Set("user_id", uid)
 		c.Next()
 	}