thread-safe database classes, created instead of last modifed date in

title

CrewDatabase.cpp

@@ -47,10 +47,14 @@ CrewDatabase::~CrewDatabase()
 
 QStringList CrewDatabase::getCrews()
 {
+    mutex.lock();
     return crewDB->childKeys();
+    mutex.unlock();
 }
 
 void CrewDatabase::addCrew(int crewID)
 {
+    mutex.lock();
     crewDB->setValue(QString::number(crewID), crewID);
+    mutex.unlock();
 }