Network: Add add node command.

src/View/Network/GraphWidget.py

@@ -376,7 +376,12 @@ class GraphWidget(QGraphicsView):
         Returns:
             Nothing
         """
-        node = self.graph.add_node(pos.x(), pos.y())
+        node = self.graph.create_node(pos.x(), pos.y())
+        self._undo.push(
+            AddNodeCommand(
+                self.graph, node
+            )
+        )
         inode = NodeItem(node, self)
         self.scene().addItem(inode)
         self.node_items.append(inode)