fixed missing include, added build folder to gitignore

.gitignore

@@ -34,3 +34,6 @@ Makefile*
 *.qmlproject.user
 *.qmlproject.user.*
 
+# build
+build*
+

mainwindow.cpp

@@ -4,6 +4,7 @@
 #include <QFile>
 #include <QTimer>
 #include <QtNetwork/QNetworkReply>
+#include <QRegularExpression>
 
 class QNetworkReply;
 namespace yremote {