Fixed registration handler

src/db.go

@@ -126,7 +126,12 @@ func NewActivation(code string) error {
 }
 
 func UseActivation(code string) bool {
-	_, err := db.Exec(`delete from activations where code = $1`, code)
+	exists := false
+	err := db.Get(&exists, `SELECT exists(SELECT 1 FROM chats WHERE code = $1);`, code)
+	if err != nil || !exists {
+		return false
+	}
+	_, err = db.Exec(`delete from activations where code = $1`, code)
 	return err == nil
 }