Updated database initialization. Now crashing on database open or creation beacuse of not corresponding other code.
Adopted TeacherWidget.
Added insertRecord(const QVariantMap record) method to base widget, which inserts record via common QSqlQuery (not model), because there is the correct way to do it.
	modified:   mainwindow.cpp
	modified:   models/teachermodel.cpp
	modified:   widgets/basewidget.cpp
	modified:   widgets/basewidget.h
	modified:   widgets/teacherwidget.cpp