Sort ECS stuff into modules

src/systems/left_walker.rs

@@ -0,0 +1,17 @@
+use crate::components::{left_mover::LeftMover, position::Position};
+use specs::prelude::*;
+
+pub struct LeftWalker {}
+
+impl<'a> System<'a> for LeftWalker {
+    type SystemData = (ReadStorage<'a, LeftMover>, WriteStorage<'a, Position>);
+
+    fn run(&mut self, (lefty, mut pos): Self::SystemData) {
+        for (_lefty, pos) in (&lefty, &mut pos).join() {
+            pos.x -= 1;
+            if pos.x < 0 {
+                pos.x = 65;
+            }
+        }
+    }
+}

src/systems/mod.rs

@@ -0,0 +1,3 @@
+pub use left_walker::LeftWalker;
+
+pub mod left_walker;