Refactor organisation

src/fruit.rs

@@ -1,18 +1,20 @@
 use crate::{
     grid,
-    snake::{SnakeHead, Z_HEIGHT},
+    snake::{self, SnakeHead},
     tick::tick_triggered,
 };
 use bevy::prelude::*;
 use iyes_loopless::prelude::*;
 use rand::prelude::*;
 
+const Z_HEIGHT: f32 = snake::Z_HEIGHT / 2.;
+
 pub struct FruitPlugin;
 
 impl Plugin for FruitPlugin {
     fn build(&self, app: &mut App) {
         app.add_event::<EatenEvent>()
-            .add_startup_system(spawn_fruit_system)
+            .add_startup_system(spawn_fruit_system.after(snake::SystemLabel::StartUp))
             .add_system(eat_fruit_system.run_if(tick_triggered))
             .add_system(debug_eaten_event_system)
             .add_system(despawn_fruit_system)