Fixing critical API issue; resolves #26

types.go

@@ -120,12 +120,10 @@ type Video struct {
 
 // Contact object represents a contact to Telegram user
 type Contact struct {
+	UserID      int    `json:"user_id"`
 	PhoneNumber string `json:"phone_number"`
 	FirstName   string `json:"first_name"`
 	LastName    string `json:"last_name"`
-
-	// Contact's username in Telegram (might be empty).
-	Username string `json:"user_id"`
 }
 
 // Location object represents geographic position.