Do not add query to history if it was the last

Maybe people just press enter twice.

This is the behaviour of bash.

relational_gui/guihandler.py

@@ -190,7 +190,11 @@ class relForm(QtWidgets.QMainWindow):
                 self.showRelation(self.selectedRelation)
 
             if not self.multiline:
-                # Adds to history
+                # Last in history
+                item = self.ui.lstHistory.item(self.ui.lstHistory.count() - 1)
+
+                if item is None or item.text() != query:
+                    # Adds to history if it is not already the last
                     hitem = QtWidgets.QListWidgetItem(None, 0)
                     hitem.setText(query)
                     self.ui.lstHistory.addItem(hitem)