Create method that switches to the expenses window

src/main/java/no/ntnu/idatt1002/demo/view/SceneController.java

@@ -32,4 +32,12 @@ public class SceneController {
         stage.setScene(scene);
         stage.show();
     }
-}
\ No newline at end of file
+
+    public void switchExpenses(ActionEvent event) throws IOException {
+        FXMLLoader loader = new FXMLLoader(SceneController.class.getResource("/view/Expenses.fxml"));
+        Parent root = loader.load();
+        stage = (Stage)((Node)event.getSource()).getScene().getWindow();
+        scene = new Scene(root);
+        stage.setScene(scene);
+        stage.show();
+    }}
\ No newline at end of file