ADD back button to main game & PATCH broken main page

controllers/gui_controller.py

@@ -1,7 +1,7 @@
 from render.gui_renderer import GUIRenderer
 
 class GUIController:
-    def __init__(self, gui_renderer: GUIRenderer, callback_function):
+    def __init__(self, gui_renderer: GUIRenderer, callback_function, previous_states):
         self.callback_function = callback_function
 
         self.gui_renderer = gui_renderer
@@ -9,6 +9,10 @@ class GUIController:
         self.settings_button = gui_renderer.settings_button
         self.settings_button.set_action(lambda: self.callback_function("settings_menu"))
 
+        self.back_button = gui_renderer.back_button
+        self.back_button.set_action(lambda: self.callback_function(previous_states.pop()))
+
     def update(self, event):
         self.slider.handle_event(event)
-        self.settings_button.handle_event(event)
+        self.settings_button.handle_event(event)
+        self.back_button.handle_event(event)