feat: show new message count & new user count in home page

model/user.go

@@ -103,6 +103,9 @@ func (user *User) Insert() error {
 		}
 	}
 	err = DB.Create(user).Error
+	if err == nil {
+		common.UserCount += 1 // We don't need to use atomic here, because it's not a critical value
+	}
 	return err
 }