Implemented logging mechanism (#785)

gpt4all-chat/logger.h

@@ -0,0 +1,18 @@
+#ifndef LOGGER_H
+#define LOGGER_H
+#include <QFile>
+
+class Logger
+{
+    QFile m_file;
+
+    static void messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg);
+
+public:
+    static Logger *globalInstance();
+
+    explicit Logger();
+    friend class MyLogger;
+};
+
+#endif // LOGGER_H